Actinic ray-sensitive or radiation-sensitive resin composition, actinic ray-sensitive or radiation-sensitive film, pattern forming method, and photo mask

ABSTRACT

The present invention provides an actinic ray-sensitive or radiation-sensitive resin composition including, as a solvent, ethyl lactate in which one of an L isomer or a D isomer of optical isomers has a ratio of 1% or more higher than that of the other, an actinic ray-sensitive or radiation-sensitive film formed using the actinic ray-sensitive or radiation-sensitive resin composition, a pattern forming method, a photo mask, and a method for producing an electronic device.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation of International Application No.PCT/JP2019/025174 filed on Jun. 25, 2019, and claims priority fromJapanese Patent Application No. 2018-125419 filed on Jun. 29, 2018, theentire content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an actinic ray-sensitive orradiation-sensitive resin composition, an actinic ray-sensitive orradiation-sensitive film, a pattern forming method, and a photo mask.

2. Description of the Related Art

In processes for manufacturing semiconductor devices such as anintegrated circuit (IC) and a large scale integrated circuit (LSI),microfabrication by lithography using a photoresist composition has beenperformed in the related art. In recent years, along with the highintegration of integrated circuits, the formation of ultrafine patternsin a submicron region or quarter micron region has been required. Alongwith this, the exposure wavelength also tends to be shortened fromg-line to i-line, and further to KrF excimer laser light, and anexposure machine using an ArF excimer laser having a wavelength of 193nm as a light source is currently being developed. In addition,development of a so-called liquid immersion method in which a liquidhaving a high refractive index (hereinafter also referred to as an“immersion liquid”) is filled between a projection lens and a sample asa technique for further enhancing resolving power has been in progresssince the related art.

Furthermore, at present, the development of lithography using electronbeams (EB), X-rays, extreme ultraviolet rays (EUV), or the like inaddition to excimer laser light is also in progress. Along with this,chemically amplified resist compositions that are effectively sensitiveto various radiations have been developed.

Ethyl lactate (EL) is known as a solvent included in the chemicallyamplified resist composition.

For example, JP2007-171466A describes a resist composition includingethyl acetate as an organic solvent and an antioxidant, and alsodescribes that a resist composition formed by dissolution in an organicsolvent including ethyl lactate, in which a dimensional variation of aresist pattern of the resist composition over time is suppressed, isprovided.

In addition, JP2007-025467A describes a resist composition including anorganic solvent including ethyl lactate and acetic acid, and alsodescribes that a resist composition formed by dissolution in an organicsolvent including ethyl lactate, in which the sensitivity deteriorationof the resist composition over time is suppressed and the resistcomposition has lithographic characteristics to be required, isprovided.

SUMMARY OF THE INVENTION

As described in JP2007-171466A and JP2007-025467A, attention is paid tofavorably perform pattern formation after a resist composition is storedfor a certain period of time, but along with a recent demand forultrafine pattern formation, a further improvement is desired.

An object of the present invention is to provide an actinicray-sensitive or radiation-sensitive resin composition capable ofexerting a good sensitivity, a good resolution, and a good pattern shapesimultaneously at the same time in an extremely high dimension even in acase where the composition has been stored for a certain period of time;and an actinic ray-sensitive or radiation-sensitive film, a patternforming method, and a photo mask, each using the composition.

The present inventors have conducted studies, and as a result, they havefound that by using an actinic ray-sensitive or radiation-sensitiveresin composition including, as a solvent, ethyl lactate in which one ofan L isomer or a D isomer of optical isomers has a ratio of 1% or morehigher than that of the other, it is possible to exert a goodsensitivity, a good resolution, and a good pattern shape simultaneouslyin an extremely high dimension even in a case where the composition hasbeen stored for a certain period of time, thereby completing the presentinvention.

That is, the present inventors have found that the object can beaccomplished by the following configurations.

[1] An actinic ray-sensitive or radiation-sensitive resin composition,comprising, as a solvent, ethyl lactate in which one of an L isomer or aD isomer of optical isomers has a ratio of 1% or more higher than thatof the other.

[2] The actinic ray-sensitive or radiation-sensitive resin compositionas described in [1], in which a content of ethyl lactate is 10% by massor more with respect to a total amount of the solvent.

[3] The actinic ray-sensitive or radiation-sensitive resin compositionas described in [1] or [2], further comprising a resin having asolubility in a developer which is changed by an action of an acid.

[4] The actinic ray-sensitive or radiation-sensitive resin compositionas described in any one of [1] to [3], further comprising a compoundthat generates an acid upon irradiation with actinic rays or radiation.

[5] The actinic ray-sensitive or radiation-sensitive resin compositionas described in any one of [1] to [4], further comprising an aciddiffusion control agent.

[6] The actinic ray-sensitive or radiation-sensitive resin compositionas described in [4] or [5], in which an acid produced from the compoundthat generates an acid upon irradiation with actinic rays or radiationhas a pKa from −10 to 5.

[7] The actinic ray-sensitive or radiation-sensitive resin compositionas described in any one of [3] to [6],

in which the resin having a solubility in a developer which is changedby the action of an acid is a resin having a group having a polaritywhich is increased upon decomposition by an action of an acid, and thegroup having a polarity which is increased upon decomposition by anaction of an acid has an acetal structure.

[8] The actinic ray-sensitive or radiation-sensitive resin compositionas described in any one of [1] to [7], further comprising a compoundhaving a lactone structure or a sultone structure.

[9] The actinic ray-sensitive or radiation-sensitive resin compositionas described in any one of [1] to [8],

in which the actinic ray-sensitive or radiation-sensitive resincomposition is used for manufacturing a photo mask.

[10] An actinic ray-sensitive or radiation-sensitive film formed usingthe actinic ray-sensitive or radiation-sensitive resin composition asdescribed in any one of [1] to [8].

[11] A pattern forming method comprising:

a resist film forming step of forming a resist film using the actinicray-sensitive or radiation-sensitive resin composition as described inany one of [1] to [8];

an exposing step of exposing the resist film; and

a developing step of developing the exposed resist film using adeveloper.

[12] A photo mask manufactured using the pattern forming method asdescribed in [11].

According to the present invention, it is possible to provide an actinicray-sensitive or radiation-sensitive resin composition capable ofexerting a good sensitivity, a good resolution, and a good pattern shapesimultaneously in an extremely high dimension even in a case where thecomposition has been stored for a certain period of time; and an actinicray-sensitive or radiation-sensitive film, a pattern forming method, anda photo mask, each using the composition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be described in detail.

Description of configuration requirements described below is made on thebasis of representative embodiments of the present invention in somecases, but the present invention is not limited to such embodiments.

“Actinic rays” or “radiation” in the present specification means, forexample, a bright line spectrum of a mercury lamp, far ultraviolet raystypified by an excimer laser, extreme ultraviolet rays (EUV light),X-rays, soft X-rays, electron beams (EB), or the like. “Light” in thepresent specification means actinic rays or radiation. Unless otherwisespecified, “exposure” in the present specification encompasses not onlyexposure by a bright line spectrum of a mercury lamp, far ultravioletrays typified by an excimer laser, extreme ultraviolet rays (EUV),X-rays, or the like, but also lithography by particle rays such aselectron beams and ion beams.

In the present specification, a numerical range expressed using “to” isused in a meaning of a range that includes the preceding and succeedingnumerical values of “to” as the lower limit value and the upper limitvalue, respectively.

In the present specification, (meth)acrylate represents at least one ofacrylate or methacrylate. In addition, (meth)acrylic acid represents atleast one of acrylic acid or methacrylic acid.

In the present specification, the weight-average molecular weight (Mw),the number-average molecular weight (Mn), and the dispersity (alsoreferred to as a molecular weight distribution) (Mw/Mn) of a resin areeach defined as a value converted in terms of polystyrene by means ofgel permeation chromatography (GPC) measurement (solvent:tetrahydrofuran, flow amount (amount of a sample injected): 10 μL,columns: TSK gel Multipore HXL-M manufactured by Tosoh Corporation,column temperature: 40° C., flow rate: 1.0 mL/min, detector:differential refractive index detector) using a GPC apparatus (HLC-8120GPC manufactured by Tosoh Corporation).

In citations for a group (atomic group) in the present specification, ina case where the group is cited without specifying whether it issubstituted or unsubstituted, the group includes both a group having nosubstituent and a group having a substituent. For example, an “alkylgroup” includes not only an alkyl group having no substituent(unsubstituted alkyl group), but also an alkyl group having asubstituent (substituted alkyl group). In addition, an “organic group”in the present specification refers to a group including at least onecarbon atom.

The actinic ray-sensitive or radiation-sensitive resin compositionaccording to an embodiment of the present invention (hereinafter alsoreferred to as the “composition of the embodiment of the presentinvention”) is an actinic ray-sensitive or radiation-sensitive resincomposition including, as a solvent, ethyl lactate in which one of an Lisomer or a D isomer of optical isomers has a ratio of 1% or more higherthan that of the other.

As a result of intensive studies conducted by the present inventors,although a detailed reason is unclear, it has been found that thestorage stability of ethyl lactate in which one of an L isomer or a Disomer of optical isomers has a ratio of 1% or more higher than that ofthe other is very good.

Due to the good storage stability of ethyl lactate, it is presumed thatethyl lactate contributes to the good storage stability of thecomposition even in a case where it is used as a solvent for thecomposition of the embodiment of the present invention, and it ispossible to obtain an effect that a good sensitivity, a good resolution,and a good pattern shape can be exerted simultaneously in a very highdimension even in a case where the composition has been stored for acertain period of time.

The composition of the embodiment of the present invention is preferablya resist composition, and may be either a positive tone resistcomposition or a negative tone resist composition. In addition, thecomposition may be either a resist composition for alkali development ora resist composition for organic solvent development. Among those, thepositive tone resist composition, which is a resist composition foralkali development, is preferable.

Furthermore, the composition of the embodiment of the present inventionis preferably a chemically amplified resist composition, and morepreferably a chemically amplified positive tone resist composition.

[Solvent]

The composition of the embodiment of the present invention usuallycontains a solvent.

The solvent includes ethyl lactate (hereinafter also referred to as“ethyl lactate having an optical purity of 1% or more”) in which one ofan L isomer or a D isomer of optical isomers has a ratio of 1% or morehigher than that of the other.

The ratio of one thereof represents a content ratio (mass ratio) of theL isomer or D isomer with respect to the total amount of ethyl lactate.

In the present invention, the ratio of the L isomer to the total amountof ethyl lactate may be 1% or more higher than the ratio of the D isomerto the total amount of ethyl lactate, and the ratio of the D isomer tothe total amount of ethyl lactate may be 1% or more higher than theratio of L isomer to the total amount of ethyl lactate.

The optical purity of ethyl lactate in the solvent is 1% or more,preferably 20% or more, and more preferably 50% or more.

The upper limit value of the optical purity of ethyl lactate in thesolvent is not particularly limited, but is 100% or less, and typically99% or less.

The optical purity can be measured by chiral gas chromatography (GC).

As ethyl lactate having an optical purity of 1% or more, a commerciallyavailable of ethyl lactate can also be used, and ethyl lactate can beproduced from a racemate of ethyl lactate using an enzyme.

In addition, it is also possible to produce ethyl lactate having anoptical purity of 1% or more by producing lactic acid having a highoptical purity using bacteria and subjecting the obtained lactic acid toethyl esterification.

Moreover, with regard to ethyl lactate having an optical purity of 1% ormore, as a method for adjusting the optical purity, a commerciallyavailable product may be used as it is in a case where ethyl lactatehaving a desired optical purity is on the market, and ethyl lactatehaving a specific optical purity may be produced by the method or thelike. In addition, ethyl lactate having a specific optical purity mayalso be mixed with ethyl lactate having a different optical purity (forexample, a racemate of ethyl lactate having an optical purity of 0) toobtain ethyl lactate having a desired optical purity.

The solvent may include only ethyl lactate having an optical purity of1% or more, and may also include a solvent other than ethyl lactate(hereinafter also referred to as “another solvent”), in addition toethyl lactate having an optical purity of 1% or more.

Examples of such another solvent include organic solvents such asalkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkylether, alkyl lactic acid ester other than ethyl lactate, alkylalkoxypropionate, a cyclic lactone (preferably having 4 to 10 carbonatoms), a monoketone compound (preferably having 4 to 10 carbon atoms)which may have a ring, alkylene carbonate, alkyl alkoxyacetate, andalkyl pyruvate.

As the organic solvent, a mixed solvent obtained by mixing a solventhaving a hydroxyl group in the structure and a solvent having nohydroxyl group may be used.

As the solvent having a hydroxyl group and the solvent having nohydroxyl group, the above-mentioned exemplary compounds can beappropriately selected, but as the solvent including a hydroxyl group,alkylene glycol monoalkyl ether or alkyl lactate is preferable, andpropylene glycol monomethyl ether (PGME), propylene glycol monoethylether (PGEE), or methyl 2-hydroxyisobutyrate is more preferable.Further, as the solvent having no hydroxyl group, alkylene glycolmonoalkyl ether acetate, alkyl alkoxypropionate, a monoketone compoundwhich may have a ring, a cyclic lactone, alkyl acetate, or the like ispreferable, and among these, propylene glycol monomethyl ether acetate(PGMEA), ethyl ethoxypropionate, 2-heptanone, γ-butyrolactone,cyclohexanone, cyclopentanone, or butyl acetate is more preferable, andpropylene glycol monomethyl ether acetate, γ-butyrolactone, ethylethoxypropionate, cyclohexanone, cyclopentanone, or 2-heptanone arestill more preferable. As a solvent having no hydroxyl group, propylenecarbonate is also preferable.

A mixing ratio (mass ratio) of the solvent having a hydroxyl group tothe solvent having no hydroxyl group is 1/99 to 99/1, preferably 10/90to 90/10, and more preferably 20/80 to 60/40. A mixed solvent containing50% by mass or more of the solvent having no hydroxyl group ispreferable from the viewpoint of coating evenness.

The solvent preferably contains propylene glycol monomethyl etheracetate, and may be either a single solvent of propylene glycolmonomethyl ether acetate or a mixed solvent of two or more kindscontaining propylene glycol monomethyl ether acetate.

The content of ethyl lactate having an optical purity of 1% or more ispreferably 10% by mass or more, more preferably 20% by mass or more, andstill more preferably 50% by mass or more with respect to the totalamount of the solvent.

[Resin Having Solubility in Developer which is Changed by Action ofAcid]

The actinic ray-sensitive or radiation-sensitive resin composition ofthe embodiment of the present invention preferably contains a resinhaving a solubility in a developer which is changed by the action of anacid.

The resin having a solubility in a developer which is changed by theaction of an acid may be either a resin having a solubility in adeveloper which is increased by the action of an acid or a resin havinga solubility in a developer which is decreased by the action of an acid.

Examples of the resin having a solubility in a developer which ischanged by the action of an acid include a resin having a group(hereinafter also referred to as an “acid-decomposable group”) having apolarity which is increased upon decomposition by the action of an acid(hereinafter also referred to as an “acid-decomposable resin” or a“resin (A)”), or a resin having a structure which is changed by theaction of an acid to decrease the solubility in a developer (forexample, a resin having a structure which is changed by a crosslinkingreaction with a crosslinking agent by the action of an acid and a resinhaving a structure which is changed by a crosslinking reaction betweenresins having crosslinkable groups).

In a case where the resin having a solubility in a developer which ischanged by the action of an acid is the resin (A), in the patternforming method of an embodiment of the present invention, typically, apositive tone pattern is suitably formed in a case where an alkalideveloper is adopted as the developer, and a negative tone pattern issuitably formed in a case where an organic developer is adopted as thedeveloper.

In a case where the resin having a solubility in a developer which ischanged by the action of an acid is a resin having a structure which ischanged by the action of an acid to decrease the solubility in adeveloper, in the pattern forming method of the embodiment of thepresent invention, typically, a negative tone pattern is suitably formedin a case where an alkali developer is adopted as the developer, and thenegative tone pattern is also suitably formed in a case where an organicdeveloper is used as the developer.

Hereinbelow, the resin (A) which is a preferred embodiment will bedescribed below.

The resin (A) preferably has a repeating unit having anacid-decomposable group.

As the resin (A), a known resin can be appropriately used. For example,the known resins disclosed in paragraphs [0055] to [0191] of thespecification of US2016/0274458A1, paragraphs [0035] to [0085] of thespecification of US2015/0004544A1, and paragraphs [0045] to [0090] ofthe specification of US2016/0147150A1 can be suitably used as the resin(A).

The acid-decomposable group preferably has a structure in which a polargroup is protected with a group (leaving group) that leaves upondecomposition by the action of an acid.

Examples of the polar group include an acidic group (typically a groupwhich dissociates in a 2.38%-by-mass aqueous tetramethylammoniumhydroxide solution), such as a carboxyl group, a phenolic hydroxylgroup, a fluorinated alcohol group, a sulfonic acid group, a sulfonamidogroup, a sulfonylimido group, an (alkylsulfonyl)(alkylcarbonyl)methylenegroup, an (alkylsulfonyl)(alkylcarbonyl)imido group, abis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imido group, abis(alkylsulfonyl)methylene group, a bis(alkylsulfonyl)imido group, atris(alkylcarbonyl)methylene group, and a tris(alkylsulfonyl)methylenegroup, and an alcoholic hydroxyl group.

Moreover, the alcoholic hydroxyl group refers to a hydroxyl group bondedto a hydrocarbon group, which is a hydroxyl group other than a hydroxylgroup (phenolic hydroxyl group) directly linked to an aromatic ring,from which an aliphatic alcohol group (for example, ahexafluoroisopropanol group) having the α-position substituted with anelectron-withdrawing group such as a fluorine atom is excluded as ahydroxyl group. The alcoholic hydroxyl group is preferably a hydroxylgroup having an acid dissociation constant (pKa) from 12 to 20.

Among those, as the polar group, the carboxyl group, the phenolichydroxyl group, the fluorinated alcohol group (preferably thehexafluoroisopropanol group), or the sulfonic acid group is preferable.

Examples of the group that leaves upon decomposition by the action of anacid (leaving group) include groups represented by Formulae (Y1) to(Y4).

—C(Rx₁)(Rx₂)(Rx₃)  Formula (Y1):

—C(═O)OC(Rx₁)(Rx₂)(Rx₃)  Formula (Y2):

—C(R₃₆)(R₃₇)(OR₃₈)  Formula (Y3):

—C(Rn)(H)(Ar)  Formula (Y4):

In Formula (Y1) and Formula (Y2), Rx₁ to Rx₃ each independentlyrepresent an (linear or branched) alkyl group or a (monocyclic orpolycyclic) cycloalkyl group. Further, in a case where all of Rx₁ to Rx₃are (linear or branched) alkyl groups, it is preferable that at leasttwo of Rx₁, . . . , or Rx₃ are methyl groups.

Among those, Rx₁ to Rx₃ each independently preferably represent a linearor branched alkyl group, and Rx₁ to Rx₃ each independently morepreferably represent a linear alkyl group.

Two of Rx₁ to Rx₃ may be bonded to each other to form a monocycle orpolycycle.

As the alkyl group of each of Rx₁ to Rx₃, an alkyl group having 1 to 4carbon atoms, such as a methyl group, an ethyl group, an n-propyl group,an isopropyl group, an n-butyl group, an isobutyl group, and a t-butylgroup, is preferable.

As the cycloalkyl group of each of Rx₁ to Rx₃, a monocyclic cycloalkylgroup such as a cyclopentyl group and a cyclohexyl group, or apolycyclic cycloalkyl group such as a norbornyl group, atetracyclodecanyl group, a tetracyclododecanyl group, and an adamantylgroup is preferable.

As the cycloalkyl group formed by the bonding of two of Rx₁ to Rx₃, amonocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexylgroup, and a polycyclic cycloalkyl group such as a norbornyl group, atetracyclodecanyl group, a tetracyclododecanyl group, and an adamantylgroup are preferable, and a monocyclic cycloalkyl group having 5 or 6carbon atoms is more preferable.

In the cycloalkyl group formed by the bonding of two of Rx₁ to Rx₃, forexample, a group in which one of the methylene groups constituting thering may be substituted with a heteroatom such as an oxygen atom or agroup having a heteroatom, such as a carbonyl group. With regard to thegroup represented by Formula (Y1) or Formula (Y2), for example, anaspect in which Rx₁ is a methyl group or an ethyl group, and Rx₂ and Rx₃are bonded to each other to form a cycloalkyl group is preferable.

In Formula (Y3), R₃₆ to R₃₈ each independently represent a hydrogen atomor a monovalent organic group. R₃₇ and R₃₈ may be bonded to each otherto form a ring. Examples of the monovalent organic group include analkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and analkenyl group. It is also preferable that R₃₆ is a hydrogen atom.

As Formula (Y3), a group represented by Formula (Y3-1) is preferable.

Here, L₁ and L₂ each independently represent a hydrogen atom, an alkylgroup, a cycloalkyl group, an aryl group, or a group formed bycombination thereof (for example, a group formed by a combination of analkyl group and an aryl group).

M represents a single bond or a divalent linking group.

Q represents an alkyl group which may include a heteroatom, a cycloalkylgroup which may include a heteroatom, an aryl group which may include aheteroatom, an amino group, an ammonium group, a mercapto group, a cyanogroup, an aldehyde group, or a group formed by combination thereof (forexample, a group formed by a combination of an alkyl group and acycloalkyl group).

In the alkyl group and the cycloalkyl group, for example, one of themethylene groups may be substituted with a heteroatom such as an oxygenatom or a group having a heteroatom, such as a carbonyl group.

In addition, it is preferable that one of L₁ or L₂ is a hydrogen atom,and the other is an alkyl group, a cycloalkyl group, an aryl group, or agroup formed by a combination of an alkylene group and an aryl group.

At least two of Q, M, or L₁ may be bonded to each other to form a ring(preferably a 5-membered or 6-membered ring).

From the viewpoint of pattern miniaturization, L₂ is preferably asecondary or tertiary alkyl group, and more preferably the tertiaryalkyl group. Examples of the secondary alkyl group include an isopropylgroup, a cyclohexyl group, and a norbornyl group, and examples of thetertiary alkyl group include a tert-butyl group and an adamantane group.In these aspects, since the glass transition temperature (Tg) and theactivation energy are higher, it is possible to suppress fogging inaddition to ensuring film hardness.

In Formula (Y4), Ar represents an aromatic ring group. Rn represents analkyl group, a cycloalkyl group, or an aryl group. Rn and Ar may bebonded to each other to form a non-aromatic ring. Ar is more preferablyan aryl group.

The resin (A) preferably has an acetal structure.

The acid-decomposable group preferably has an acetal structure. Theacetal structure is, for example, a structure in which a polar groupsuch as a carboxyl group, a phenolic hydroxyl group, and a fluorinatedalcohol group is protected with the group represented by Formula (Y3).

As the repeating unit having an acid-decomposable group, a repeatingunit represented by Formula (A) is preferable.

L₁ represents a divalent linking group, R₁ to R₃ each independentlyrepresent a hydrogen atom or a monovalent substituent, and R₄ representsa group that leaves upon decomposition by the action of an acid.

L₁ represents a divalent linking group. Examples of the divalent linkinggroup include —CO—, —O—, —S—, —SO—, —SO₂—, a hydrocarbon group (forexample, an alkylene group, a cycloalkylene group, an alkenylene group,and an arylene group), and a linking group in which a plurality of thesegroups are linked. Among those, L₁ is preferably —CO— or the arylenegroup.

The arylene group is preferably a phenylene group.

The alkylene group may be linear or branched. The number of carbon atomsof the alkylene group is not particularly limited, but is preferably 1to 10, more preferably 1 to 3.

R₁ to R₃ each independently represent a hydrogen atom or a monovalentsubstituent. Examples of the monovalent substituent include an alkylgroup, a cycloalkyl group, and a halogen atom.

The alkyl group may be linear or branched. The number of carbon atoms ofthe alkyl group is not particularly limited, but is preferably 1 to 10,and more preferably 1 to 3.

The cycloalkyl group may be monocyclic or polycyclic. The number ofcarbon atoms of this cycloalkyl group is preferably 3 to 8.

Examples of the halogen atom include a fluorine atom, a chlorine atom, abromine atom, and an iodine atom.

R₄ represents a group that leaves upon decomposition by the action of anacid (leaving group).

Among those, examples of the leaving group include the groupsrepresented by Formulae (Y1) to (Y4), and the group represented byFormula (Y3) is preferable.

In a case where each of the groups has a substituent, examples of thesubstituent include an alkyl group (having 1 to 4 carbon atoms), ahalogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbonatoms), a carboxyl group, and an alkoxycarbonyl group (having 2 to 6carbon atoms). The number of carbon atoms in the substituent ispreferably 8 or less.

As the repeating unit having an acid-decomposable group, a repeatingunit represented by General Formula (AI) is also preferable.

In General Formula (AI),

Xa₁ represents a hydrogen atom or an alkyl group.

T represents a single bond or a divalent linking group.

Rx₁ to Rx₃ each independently represent an (linear or branched) alkylgroup or a (monocyclic or polycyclic) cycloalkyl group. It should benoted that in a case where all of Rx₁ to Rx₃ are (linear or branched)alkyl groups, at least two of Rx₁, . . . , or Rx₃ are preferably methylgroups.

Two of Rx₁ to Rx₃ may be bonded to each other to form a (monocyclic orpolycyclic) cycloalkyl group.

Examples of the alkyl group represented by Xa₁ include a methyl groupand a group represented by —CH₂—R₁₁. R₁₁ represents a halogen atom (afluorine atom or the like), a hydroxyl group, or a monovalent organicgroup, examples thereof include an alkyl group having 5 or less carbonatoms and an acyl group having 5 or less carbon atoms, the alkyl grouphaving 3 or less carbon atoms is preferable, and a methyl group is morepreferable. Xa₁ is preferably a hydrogen atom, a methyl group, atrifluoromethyl group, or a hydroxymethyl group.

Examples of the divalent linking group of T include an alkylene group,an aromatic ring group, a —COO—Rt- group, and an —O—Rt- group. InFormulae, Rt represents an alkylene group or a cycloalkylene group.

T is preferably the single bond or the —COO—Rt- group. In a case where Trepresents the —COO—Rt- group, Rt is preferably an alkylene group having1 to 5 carbon atoms, and is more preferably a —CH₂— group, a —(CH₂)₂—group, or a —(CH₂)₃— group.

As the alkyl group of each of Rx₁ to Rx₃, an alkyl group having 1 to 4carbon atoms, such as a methyl group, an ethyl group, an n-propyl group,an isopropyl group, an n-butyl group, an isobutyl group, and a t-butylgroup, is preferable.

As the cycloalkyl group of each of Rx₁ to Rx₃, a monocyclic cycloalkylgroup such as a cyclopentyl group and a cyclohexyl group, or apolycyclic cycloalkyl group such as a norbornyl group, atetracyclodecanyl group, a tetracyclododecanyl group, and an adamantylgroup is preferable.

As the cycloalkyl group formed by the bonding of two of Rx₁ to Rx₃, amonocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexylgroup is preferable, and in addition, a polycyclic cycloalkyl group suchas a norbornyl group, a tetracyclodecanyl group, a tetracyclododecanylgroup, and an adamantyl group is preferable. Among those, a monocycliccycloalkyl group having 5 or 6 carbon atoms is preferable.

In the cycloalkyl group formed by the bonding of two of Rx₁ to Rx₃, forexample, one of the methylene groups constituting the ring may besubstituted with a heteroatom such as an oxygen atom or a group having aheteroatom, such as a carbonyl group.

With regard to the repeating unit represented by General Formula (AI),for example, an aspect in which Rx₁ is a methyl group or an ethyl group,and Rx₂ and Rx₃ are bonded to each other to form the above-mentionedcycloalkyl group is preferable.

In a case where each of the groups has a substituent, examples of thesubstituent include an alkyl group (having 1 to 4 carbon atoms), ahalogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbonatoms), a carboxyl group, and an alkoxycarbonyl group (having 2 to 6carbon atoms). The number of carbon atoms in the substituent ispreferably 8 or less.

The repeating unit represented by General Formula (AI) is preferably anacid-decomposable tertiary alkyl (meth)acrylate ester-based repeatingunit (the repeating unit in which Xa₁ represents a hydrogen atom or amethyl group, and T represents a single bond).

The resin (A) may include only one kind the repeating units having anacid-decomposable group or a combination of two or more kinds of therepeating units.

The content of the repeating unit having an acid-decomposable groupincluded in the resin (A) (in a case where a plurality of the repeatingunits having an acid-decomposable group are present, a total contentthereof) is preferably 10% to 90% by mole, more preferably 20% to 80% bymole, and still more preferably 30% to 70% by mole, with respect to allthe repeating units of the resin (A).

(Repeating Unit Having Lactone Group or Sultone Group)

The resin (A) may further have a repeating unit having a lactone groupor a sultone group.

As the lactone group or the sultone group, any of groups having alactone structure or a sultone structure can be used, but a group havinga 5- to 7-membered ring lactone structure or a 5- to 7-membered ringsultone structure is preferable; and the group in which another ringstructure is fused to the 5- to 7-membered ring lactone structure so asto form a bicyclo structure or a spiro structure, or the group in whichanother ring structure is fused to the 5- to 7-membered ring sultonestructure so as to form a bicyclo structure or a spiro structure is morepreferable. The resin (A) more preferably has a repeating unit having agroup having lactone structure represented by any of General Formulae(LC1-1) to (LC1-21) or a group having a sultone structure represented byany of General Formula (SL1-1), . . . , or (SL1-3). Further, a grouphaving a lactone structure or a sultone structure may be bonded directlyto the main chain. As the preferred structure, groups represented byGeneral Formula (LC1-1), General Formula (LC1-4), General Formula(LC1-5), General Formula (LC1-6), General Formula (LC1-13), and GeneralFormula (LC1-14) are preferable.

The lactone structural moiety or the sultone structural moiety may havea substituent (Rb₂). Preferred examples of the substituent (Rb₂) includean alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, analkoxycarbonyl group having 1 to 8 carbon atoms, a carboxyl group, ahalogen atom, a hydroxyl group, a cyano group, and an acid-decomposablegroup. n₂ represents an integer of 0 to 4. In a case where n₂ is 2 ormore, Rb₂'s which are present in plural number may be different fromeach other and Rb₂'s which are present in plural number may be bonded toeach other to form a ring.

Examples of the repeating unit having the group having a lactonestructure or a sultone structure include a repeating unit represented byGeneral Formula (AI).

In General Formula (AI), Rb₀ represents a hydrogen atom, a halogen atom,or an alkyl group having 1 to 4 carbon atoms.

Preferred examples of a substituent which may be contained in the alkylgroup of Rb₀ include a hydroxyl group and a halogen atom.

Examples of the halogen atom of Rb₀ include a fluorine atom, a chlorineatom, a bromine atom, and an iodine atom. Rb₀ is preferably the hydrogenatom or a methyl group.

Ab represents a single bond, an alkylene group, a divalent linking grouphaving a monocyclic or polycyclic alicyclic hydrocarbon structure, anether group, an ester group, a carbonyl group, a carboxyl group, or adivalent group formed by combination thereof. Among those, the singlebond or a linking group represented by -Ab₁-CO₂— is preferable. Ab₁ is alinear or branched alkylene group or a monocyclic or polycycliccycloalkylene group, and preferably a methylene group, an ethylenegroup, a cyclohexylene group, an adamantylene group, or a norbornylenegroup.

V represents a group having a lactone structure or a sultone structure.

As the group having the lactone structure or the sultone structure of V,a group represented by any of General Formulae (LC1-1) to (LC1-21) andGeneral Formulae (SL1-1) to (SL1-3) is preferable.

The repeating unit having the group having a lactone structure or asultone structure usually has optical isomers, and any of opticalisomers may be used. In addition, one kind of optical isomers may beused singly or a plurality of kinds of optical isomers may be mixed andused. In a case where one kind of optical isomers is mainly used, anoptical purity (ee) thereof is preferably 90 or more, and morepreferably 95 or more.

Specific examples of the repeating unit having the group having alactone structure or a sultone structure are shown below, but thepresent invention is not limited thereto. In the formulae, Rx representsH, CH₃, CH₂OH, or CF₃.

The content of the repeating unit having a lactone group or a sultonegroup is preferably 1% to 60% by mole, more preferably 5% to 50% bymole, and still more preferably 10% to 40% by mole, with respect to allthe repeating units in the resin (A).

(Repeating Unit Having Acid Group)

The resin (A) may have a repeating unit having an acid group.

As the acid group, an acid group having an acid dissociation constant(pKa) of 13 or less is preferable.

The pKa is the same as the pKa in the pKa of the acid produced from aphotoacid generator which will be described later.

As the repeating unit having an acid group, a repeating unit representedby Formula (B) is preferable.

R₃ represents a hydrogen atom or a monovalent organic group.

As the monovalent organic group, a group represented by -L₄-R₈ ispreferable. L₄ represents a single bond or an ester group. Examples ofR₈ include an alkyl group, a cycloalkyl group, an aryl group, and agroup formed by combination thereof.

R₄ and R₅ each independently represent a hydrogen atom, a halogen atom,or an alkyl group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, abromine atom, or an iodine atom.

L₂ represents a single bond or an ester group.

L₃ represents an (n+m+1)-valent aromatic hydrocarbon ring group or an(n+m+1)-valent alicyclic hydrocarbon ring group. Examples of thearomatic hydrocarbon ring group include a benzene ring group and anaphthalene ring group. The alicyclic hydrocarbon ring group may beeither a monocycle or a polycycle, and examples thereof include acycloalkyl ring group.

R₆ represents a hydroxyl group or a fluorinated alcohol group(preferably a hexafluoroisopropanol group). In addition, in a case whereR₆ is a hydroxyl group, L₃ is preferably the (n+m+1)-valent aromatichydrocarbon ring group.

R₇ represents a halogen atom. Examples of the halogen atom include afluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

m represents an integer of 1 or more. m is preferably an integer of 1 to3, and more preferably an integer of 1 or 2.

n represents 0 or an integer of 1 or more. n is preferably an integer of1 to 4.

In addition, (n+m+1) is preferably an integer of 1 to 5.

As the repeating unit having an acid group, a repeating unit representedby General Formula (I) is also preferable.

In General Formula (I),

R₄₁, R₄₂, and R₄₃ each independently represent a hydrogen atom, an alkylgroup, a cycloalkyl group, a halogen atom, a cyano group, or analkoxycarbonyl group. It should be noted that R₄₂ may be bonded to Ar₄to form a ring, in which case R₄₂ represents a single bond or analkylene group.

X₄ represents a single bond, —COO—, or —CONR₆₄—, and R₆₄ represents ahydrogen atom or an alkyl group.

L₄ represents a single bond or an alkylene group.

Ar₄ represents an (n+1)-valent aromatic ring group, and in a case whereAr₄ is bonded to R₄₂ to form a ring, Ar₄ represents an (n+2)-valentaromatic ring group.

n represents an integer of 1 to 5.

As the alkyl group represented by each of R₄₁, R₄₂, and R₄₃ in GeneralFormula (I), an alkyl group having 20 or less carbon atoms, such as amethyl group, an ethyl group, a propyl group, an isopropyl group, ann-butyl group, a sec-butyl group, a hexyl group, a 2-ethylhexyl group,an octyl group, and a dodecyl group is preferable, an alkyl group having8 or less carbon atoms is more preferable, and an alkyl group having 3or less carbon atoms is still more preferable.

The cycloalkyl group of each of R₄₁, R₄₂, and R₄₃ in General Formula (I)may be monocyclic or polycyclic. Among those, a cycloalkyl group having3 to 8 carbon atoms, such as a cyclopropyl group, a cyclopentyl group,and a monocyclic cyclohexyl group, is preferable.

Examples of the halogen atom of each of R₄₁, R₄₂, and R₄₃ in GeneralFormula (I) include a fluorine atom, a chlorine atom, a bromine atom,and an iodine atom, and the fluorine atom is preferable.

As the alkyl group included in the alkoxycarbonyl group of each of R₄₁,R₄₂, and R₄₃ in General Formula (I), the same ones as the alkyl group ineach of R₄₁, R₄₂, and R₄₃ are preferable.

Preferred examples of the substituent in each of the groups include analkyl group, a cycloalkyl group, an aryl group, an amino group, an amidogroup, a ureido group, a urethane group, a hydroxyl group, a carboxylgroup, a halogen atom, an alkoxy group, a thioether group, an acylgroup, an acyloxy group, an alkoxycarbonyl group, a cyano group, and anitro group. The number of carbon atoms of the substituent is preferably8 or less.

Ar₄ represents an (n+1)-valent aromatic ring group. The divalentaromatic ring group in a case where n is 1 may have a substituent, andis preferably, for example, an arylene group having 6 to 18 carbonatoms, such as a phenylene group, a tolylene group, a naphthylene group,and an anthracenylene group, or an aromatic ring group including aheterocycle such as a thiophene ring, a furan ring, a pyrrole ring, abenzothiophene ring, a benzofuran ring, a benzopyrrole ring, a triazinering, an imidazole ring, a benzimidazole ring, a triazole ring, athiadiazole ring, and a thiazole ring.

Specific examples of the (n+1)-valent aromatic ring group in a casewhere n is an integer of 2 or more include groups formed by removing any(n−1) hydrogen atoms from the above-described specific examples of thedivalent aromatic ring group.

The (n+1)-valent aromatic ring group may further have a substituent.

Examples of the substituent which may be included in the alkyl group,the cycloalkyl group, the alkoxycarbonyl group, the alkylene group, andthe (n+1)-valent aromatic ring group as mentioned above include thealkyl group; the alkoxy group such as a methoxy group, an ethoxy group,a hydroxyethoxy group, a propoxy group, a hydroxypropoxy group, and abutoxy group; an aryl group such as a phenyl group; and the like, asmentioned for each of R₄₁, R₄₂, and R₄₃ in General Formula (I).

Examples of the alkyl group of R₆₄ in —CONR₆₄— represented by X₄ (R₆₄represents a hydrogen atom or an alkyl group) include an alkyl grouphaving 20 or less carbon atoms, such as a methyl group, an ethyl group,a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group,a hexyl group, a 2-ethylhexyl group, an octyl group, and a dodecylgroup, and an alkyl group having 8 or less carbon atoms is preferable.

As X₄, a single bond, —COO—, or —CONH— is preferable, and the singlebond or —COO— is more preferable.

The alkylene group for L₄ is preferably an alkylene group having 1 to 8carbon atoms, such as a methylene group, an ethylene group, a propylenegroup, a butylene group, a hexylene group, and an octylene group.

As Ar₄, an aromatic ring group having 6 to 18 carbon atoms ispreferable, and a benzene ring group, a naphthalene ring group, and abiphenylene ring group are more preferable.

The repeating unit represented by General Formula (I) preferably has ahydroxystyrene structure. That is, Ar₄ is preferably the benzene ringgroup.

The repeating unit represented by General Formula (I) is preferably arepeating unit represented by General Formula (1).

In General Formula (1),

A represents a hydrogen atom, an alkyl group, a cycloalkyl group, ahalogen atom, or a cyano group.

R represents a halogen atom, an alkyl group, a cycloalkyl group, an arylgroup, an alkenyl group, an aralkyl group, an alkoxy group, analkylcarbonyloxy group, an alkylsulfonyloxy group, an alkyloxycarbonylgroup, or an aryloxycarbonyl group, and in a case where a plurality ofR's are present, R's may be the same as or different from each other. Ina case where there are a plurality of R's, R's may be combined with eachother to form a ring. As R, the hydrogen atom is preferable.

a represents an integer of 1 to 3.

b represents an integer of 0 to (3-a).

Hereinafter, specific examples of the repeating unit represented byGeneral Formula (I) will be shown, but the present invention is notlimited thereto. In the formula, a represents 1 or 2.

Moreover, among the repeating units, the repeating units specificallydescribed below are preferable. In the formulae, R represents a hydrogenatom or a methyl group, and a represents 2 or 3.

The content of the repeating unit having an acid group is preferably 10%to 80% by mole, more preferably 15% to 75% by mole, and still morepreferably 20% to 70% by mole, with respect to all the repeating unitsin the resin (A).

The resin (A) may have a variety of repeating units, in addition to theabove-mentioned repeating structural units, for the purpose of adjustingdry etching resistance, suitability for a standard developer,adhesiveness to a substrate, a resist profile, resolving power, heatresistance, sensitivity, and the like; and other purposes.

The resin (A) can be synthesized in accordance with an ordinary method(for example, radical polymerization). Examples of the general synthesismethod include (1) a batch polymerization method in which polymerizationis performed by dissolving monomer species and an initiator in a solventand heating the solution, and (2) a dropwise addition polymerizationmethod in which a solution containing monomer species and an initiatoris added dropwise to a heating solvent for 1 to 10 hours.

The weight-average molecular weight (Mw) of the resin (A) is preferably1,000 to 200,000, more preferably 2,000 to 30,000, and still morepreferably 3,000 to 25,000. The dispersity (Mw/Mn) is usually 1.0 to3.0, preferably 1.0 to 2.6, more preferably 1.0 to 2.0, and still morepreferably 1.1 to 2.0.

The resin (A) may be used singly or in combination of two or more kindsthereof.

The content of the resin (A) in the composition of the embodiment of thepresent invention is usually 20% by mass or more, preferably 40% by massor more, more preferably 50% by mass or more, and still more preferably60% by mass or more, with respect to the total solid content. The upperlimit is not particularly limited, but is preferably 99.5% by mass orless, more preferably 99% by mass or less, and still more preferably 98%by mass or less.

In addition, the total solid content of the composition of theembodiment of the present invention means other components (componentsthat can constitute an actinic ray-sensitive or radiation-sensitivefilm) excluding the solvent.

[Compound that Generates Acid Upon Irradiation with Actinic Rays orRadiation]

The actinic ray-sensitive or radiation-sensitive resin composition ofthe embodiment of the present invention preferably contains a compoundthat generates an acid upon irradiation with actinic rays or radiation(hereinafter also referred to as a “photoacid generator” or a “photoacidgenerator (B)”).

The photoacid generator is a compound that generates an acid uponirradiation with actinic rays or radiation.

As the photoacid generator, a compound that generates an organic acidupon irradiation with actinic rays or radiation is preferable. Examplesthereof include a sulfonium salt compound, an iodonium salt compound, adiazonium salt compound, a phosphonium salt compound, an imidosulfonatecompound, an oxime sulfonate compound, a diazodisulfone compound, adisulfone compound, and an o-nitrobenzyl sulfonate compound.

As the photoacid generators, known compounds that generate an acid uponirradiation with actinic rays or radiation can be used singly or as amixture thereof, appropriately selected and used. For example, the knowncompounds disclosed in paragraphs [0125] to [0319] of the specificationof US2016/0070167A1, paragraphs [0086] to [0094] of the specification ofUS2015/0004544A1, and paragraphs [0323] to [0402] of the specificationof US2016/0237190A1 can be suitably used.

As the photoacid generator, for example, a compound represented byGeneral Formula (ZI), General Formula (ZII), or General Formula (ZIII)is preferable.

In General Formula (ZI),

R₂₀₁, R₂₀₂, and R₂₀₃ each independently represent an organic group.

The organic group as each of R₂₀₁, R₂₀₂, and R₂₀₃ generally has 1 to 30carbon atoms, and preferably has 1 to 20 carbon atoms.

In addition, two of R₂₀₁ to R₂₀₃ may be bonded to each other to form aring structure, and the ring may include an oxygen atom, a sulfur atom,an ester bond, an amide bond, or a carbonyl group. Examples of the groupformed by the bonding of two of R₂₀₁ to R₂₀₃ include an alkylene group(for example, a butylene group and a pentylene group), and—CH₂—CH₂—O—CH₂—CH₂—.

Z⁻ represents an anion (preferably a non-nucleophilic anion).

Suitable aspects of the cation in General Formula (ZI) include thecorresponding groups in a compound (ZI-1), a compound (ZI-2), a compoundrepresented by General Formula (ZI-3) (compound (ZI-3)), and a compoundrepresented by General Formula (ZI-4) (compound (ZI-4)), each of whichwill be described later.

Furthermore, the photoacid generator may be a compound having aplurality of the structures represented by General Formula (ZI). Forexample, the photoacid generator may be a compound having a structure inwhich at least one of R₂₀₁, . . . , or R₂₀₃ of the compound representedby General Formula (ZI) and at least one of R₂₀₁, . . . , or R₂₀₃ ofanother compound represented by General Formula (ZI) are bonded via asingle bond or a linking group.

First, the compound (ZI-1) will be described.

The compound (ZI-1) is an arylsulfonium compound in which at least oneof R₂₀₁, . . . , or R₂₀₃ in General Formula (ZI) is an aryl group, thatis, a compound having arylsulfonium as a cation.

In the arylsulfonium compound, any of R₂₀₁ to R₂₀₃ may be an aryl group,or some of R₂₀₁ to R₂₀₃ may be an aryl group, and the rest may be analkyl group or a cycloalkyl group.

Examples of the arylsulfonium compound include a triarylsulfoniumcompound, a diarylalkylsulfonium compound, an aryldialkylsulfoniumcompound, a diarylcycloalkylsulfonium compound, and anaryldicycloalkylsulfonium compound.

As the aryl group included in the arylsulfonium compound, a phenyl groupor a naphthyl group is preferable, and the phenyl group is morepreferable. The aryl group may be an aryl group which has a heterocyclicstructure having an oxygen atom, a nitrogen atom, a sulfur atom, or thelike. Examples of the heterocyclic structure include a pyrrole residue,a furan residue, a thiophene residue, an indole residue, a benzofuranresidue, and a benzothiophene residue. In a case where the arylsulfoniumcompound has two or more aryl groups, the two or more aryl groups may bethe same as or different from each other.

The alkyl group or the cycloalkyl group contained in the arylsulfoniumcompound, as necessary, is preferably a linear alkyl group having 1 to15 carbon atoms, a branched alkyl group having 3 to 15 carbon atoms, ora cycloalkyl group having 3 to 15 carbon atoms, and examples thereofinclude a methyl group, an ethyl group, a propyl group, an n-butylgroup, a sec-butyl group, a t-butyl group, a cyclopropyl group, acyclobutyl group, and a cyclohexyl group.

The aryl group, the alkyl group, and the cycloalkyl group of each ofR₂₀₁ to R₂₀₃ may each independently have an alkyl group (for example,having 1 to 15 carbon atoms), a cycloalkyl group (for example, having 3to 15 carbon atoms), an aryl group (for example, having 6 to 14 carbonatoms), an alkoxy group (for example, having 1 to 15 carbon atoms), ahalogen atom, a hydroxyl group, or a phenylthio group as a substituent.

Next, the compound (ZI-2) will be described.

The compound (ZI-2) is a compound in which R₂₀₁ to R₂₀₃ in Formula (ZI)each independently represent an organic group having no aromatic ring.Here, the aromatic ring also includes an aromatic ring including aheteroatom.

The organic group having no aromatic ring as each of R₂₀₁ to R₂₀₃generally has 1 to 30 carbon atoms, and preferably has 1 to 20 carbonatoms.

R₂₀₁ to R₂₀₃ are each independently preferably an alkyl group, acycloalkyl group, an allyl group, or a vinyl group, more preferably alinear or branched 2-oxoalkyl group, a 2-oxocycloalkyl group, or analkoxycarbonylmethyl group, and still more preferably the linear orbranched 2-oxoalkyl group.

Preferred examples of the alkyl group and the cycloalkyl group of eachof R₂₀₁ to R₂₀₃ include a linear alkyl group having 1 to 10 carbon atomsor branched alkyl group having 3 to 10 carbon atoms (for example, amethyl group, an ethyl group, a propyl group, a butyl group, and apentyl group), and a cycloalkyl group having 3 to 10 carbon atoms (forexample, a cyclopentyl group, a cyclohexyl group, and a norbornylgroup).

R₂₀₁ to R₂₀₃ may be further substituted with a halogen atom, an alkoxygroup (for example, having 1 to 5 carbon atoms), a hydroxyl group, acyano group, or a nitro group.

Next, the compound (ZI-3) will be described.

In General Formula (ZI-3), M represents an alkyl group, a cycloalkylgroup, or an aryl group, and in a case where M has a ring structure, thering structure may include at least one of an oxygen atom, a sulfuratom, an ester bond, an amide bond, or a carbon-carbon double bond.R_(1c) and R_(2c) each independently represent a hydrogen atom, an alkylgroup, a cycloalkyl group, a halogen atom, a cyano group, or an arylgroup. R_(1c) and R_(2c) may be bonded to each other to form a ring.R_(x) and R_(y) each independently represent an alkyl group, acycloalkyl group, or an alkenyl group. R_(x) and R_(y) may be bonded toeach other to form a ring. In addition, at least two selected from M,R_(1c), or R_(2c) may be bonded to each other to form a ring structure,and the ring structure may include a carbon-carbon double bond. Z⁻represents an anion.

In General Formula (ZI-3), as the alkyl group and the cycloalkyl grouprepresented by M, a linear alkyl group having 1 to 15 carbon atoms(preferably having 1 to 10 carbon atoms), a branched alkyl group having3 to 15 carbon atoms (preferably having 3 to 10 carbon atoms), or acycloalkyl group having 3 to 15 carbon atoms (preferably having 1 to 10carbon atoms) is preferable, and specific examples thereof include amethyl group, an ethyl group, a propyl group, an n-butyl group, asec-butyl group, a t-butyl group, a cyclopropyl group, a cyclobutylgroup, a cyclohexyl group, and a norbornyl group.

The aryl group represented by M is preferably a phenyl group or anaphthyl group, and more preferably the phenyl group. The aryl group maybe an aryl group which has a heterocyclic structure having an oxygenatom, a sulfur atom, or the like. Examples of the heterocyclic structureinclude a furan ring, a thiophene ring, a benzofuran ring, and abenzothiophene ring.

M may further have a substituent. In this aspect, examples of M includea benzyl group.

In addition, in a case where M has a ring structure, the ring structuremay include at least one of an oxygen atom, a sulfur atom, an esterbond, an amide bond, or a carbon-carbon double bond.

Examples of the alkyl group, the cycloalkyl group, and the aryl grouprepresented by each of R_(1c) and R_(2c) include the same ones as thosedescribed above for M, and preferred aspects thereof are also the same.Further, R_(1c) and R_(2c) may be bonded to each other to form a ring.

Examples of the halogen atom represented by each of R_(1c) and R_(2c)include a fluorine atom, a chlorine atom, a bromine atom, and an iodineatom.

Examples of the alkyl group and the cycloalkyl group represented by eachof R_(x) and R_(y) include the same ones as those described above for M,and preferred aspects thereof are also the same.

The alkenyl group represented by each of R_(x) and R_(y) is preferablyan allyl group or a vinyl group.

R_(x) and R_(y) may further have a substituent. In this aspect, examplesof each of R_(x) and R_(y) include a 2-oxoalkyl group or analkoxycarbonylalkyl group.

Examples of the 2-oxoalkyl group represented by each of R_(x) and R_(y)include those having 1 to 15 carbon atoms (preferably having 1 to 10carbon atoms), and specifically a 2-oxopropyl group and a 2-oxobutylgroup.

Examples of the alkoxycarbonylalkyl group represented by each of R_(x)and R_(y) include those having 1 to 15 carbon atoms (preferably having 1to 10 carbon atoms). In addition, R_(x) and R_(y) may be bonded to eachother to form a ring.

The ring structure formed by the mutual linkage of R_(x) and R_(y) mayinclude an oxygen atom, a sulfur atom, an ester bond, an amide bond, ora carbon-carbon double bond.

In General Formula (ZI-3), M and R_(1c) may be bonded to each other toform a ring structure, and the ring structure formed may include acarbon-carbon double bond.

Among those, the compound (ZI-3) is preferably a compound (ZI-3A).

The compound (ZI-3A) is a compound having a phenacylsulfonium saltstructure, represented by General Formula (ZI-3A).

In General Formula (ZI-3A),

R_(1c) to R_(5c) each independently represent a hydrogen atom, an alkylgroup, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxygroup, an alkoxycarbonyl group, an alkylcarbonyloxy group, acycloalkylcarbonyloxy group, a halogen atom, a hydroxyl group, a nitrogroup, an alkylthio group, or an arylthio group.

R_(6c) and R_(7c) have the same definitions as R₂ and R₃, respectively,in General Formula (ZI-3) described above, and preferred aspects thereofare also the same.

R_(x) and R_(y) have the same definitions as R_(x) and R_(y),respectively, in General Formula (ZI-3) described above, and preferredaspects thereof are also the same.

Any two or more of R_(1c), . . . , or R_(5c), or R_(x) and R_(y) may bebonded to each other to form a ring structure, and the ring structuremay each independently include an oxygen atom, a sulfur atom, an esterbond, an amide bond, or a carbon-carbon double bond. Furthermore, R_(5c)and R_(6c), or R_(5c) and R_(x) may be bonded to each other to form aring structure, and the ring structure may each independently include acarbon-carbon double bond. In addition, R_(6c) and R_(7c) may be bondedto each other to form a ring structure.

Examples of the ring structure include an aromatic or non-aromatichydrocarbon ring, an aromatic or non-aromatic heterocycle, and apolycyclic fused ring in which two or more of these rings are combinedwith each other. Examples of the ring structure include a 3- to10-membered ring and the ring structure is preferably a 4- to 8-memberedring, and more preferably a 5- or 6-membered ring.

Examples of the group formed by the bonding of any two or more ofR_(1c), . . . , or R_(5c), R_(6c) and R_(7c), and R_(x) and R_(y)include a butylene group and a pentylene group.

As the group formed by the bonding of R_(5c) and R_(6c), and R_(5c) andR_(x), a single bond or an alkylene group is preferable. Examples of thealkylene group include a methylene group and an ethylene group.

Zc⁻ represents an anion.

Next, the compound (ZI-4) will be described.

The compound (ZI-4) is represented by General Formula (ZI-4).

In General Formula (ZI-4),

1 represents an integer of 0 to 2.

r represents an integer of 0 to 8.

R₁₃ represents a group having a hydrogen atom, a fluorine atom, ahydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, analkoxycarbonyl group, or an alkoxy group having a monocyclic orpolycyclic cycloalkyl skeleton. Such a group may have a substituent.

In a case where a plurality of R₁₄'s are present, R₁₄'s eachindependently represent an alkyl group, a cycloalkyl group, an alkoxygroup, an alkylsulfonyl group, a cycloalkylsulfonyl group, analkylcarbonyl group, an alkoxycarbonyl group, or an alkoxy group havinga monocyclic or polycyclic cycloalkyl skeleton. Such a group may have asubstituent.

R₁₅'s each independently represent an alkyl group, a cycloalkyl group,or a naphthyl group. Such a group may have a substituent. Two of R₁₅'smay be bonded to each other to form a ring. In a case where two of R₁₅'sare bonded to each other to form a ring, the ring skeleton may include aheteroatom such as an oxygen atom and a nitrogen atom. In one aspect, itis preferable that two of R₁₅'s are alkylene groups and are bonded toeach other to form a ring structure.

Z⁻ represents an anion.

In General Formula (ZI-4), the alkyl group of each of R₁₃, R₁₄, and R₁₅is linear or branched. The number of carbon atoms of the alkyl group ispreferably 1 to 10. As the alkyl group, a methyl group, an ethyl group,an n-butyl group, a t-butyl group, or the like is more preferable.

Next, General Formulae (ZII) and (ZIII) will be described.

In General Formulae (ZII) and (ZIII), R₂₀₄ to R₂₀₇ each independentlyrepresent an aryl group, an alkyl group, or a cycloalkyl group.

The aryl group of each of R₂₀₄ to R₂₀₇ is preferably a phenyl group or anaphthyl group, and more preferably the phenyl group. The aryl group ofeach of R₂₀₄ to R₂₀₇ may be an aryl group which has a heterocyclicstructure having an oxygen atom, a nitrogen atom, a sulfur atom, or thelike. Examples of the skeleton of the aryl group having a heterocyclicstructure include pyrrole, furan, thiophene, indole, benzofuran, andbenzothiophene.

As the alkyl group and the cycloalkyl group of each of R₂₀₄ to R₂₀₇, alinear alkyl group having 1 to 10 carbon atoms or branched alkyl grouphaving 3 to 10 carbon atoms (for example, a methyl group, an ethylgroup, a propyl group, a butyl group, and a pentyl group), or acycloalkyl group having 3 to 10 carbon atoms (for example, a cyclopentylgroup, a cyclohexyl group, and a norbornyl group) is preferable.

The aryl group, the alkyl group, and the cycloalkyl group of each ofR₂₀₄ to R₂₀₇ may each independently have a substituent. Examples of thesubstituent which may be contained in each of the aryl group, the alkylgroup, and the cycloalkyl group of each of R₂₀₄ to R₂₀₇ include an alkylgroup (for example, having 1 to 15 carbon atoms), a cycloalkyl group(for example, having 3 to 15 carbon atoms), an aryl group (for example,having 6 to 15 carbon atoms), an alkoxy group (for example, having 1 to15 carbon atoms), a halogen atom, a hydroxyl group, and a phenylthiogroup.

Z⁻ represents an anion.

As Z⁻ in General Formula (ZI), Z⁻ in General Formula (ZII), Zc⁻ inGeneral Formula (ZI-3), and Z⁻ in General Formula (ZI-4), an anionrepresented by General Formula (3) is preferable.

In General Formula (3),

o represents an integer of 1 to 3. p represents an integer of 0 to 10. qrepresents an integer of 0 to 10.

Xf represents a fluorine atom or an alkyl group substituted with atleast one fluorine atom. The alkyl group preferably has 1 to 10 carbonatoms, and more preferably has 1 to 4 carbon atoms. In addition, aperfluoroalkyl group is preferable as the alkyl group substituted withat least one fluorine atom.

Xf is preferably a fluorine atom or a perfluoroalkyl group having 1 to 4carbon atoms, and more preferably the fluorine atom or CF₃. Inparticular, it is preferable that both Xf's are fluorine atoms.

R₄ and R₅ each independently represent a hydrogen atom, a fluorine atom,an alkyl group, or an alkyl group substituted with at least one fluorineatom. In a case where a plurality of each of R₄'s and R₅'s are present,R₄'s and R₅'s may be the same as or different from each other.

The alkyl group represented by each of R₄ and R₅ may have a substituent,and preferably has 1 to 4 carbon atoms. R₄ and R₅ are each preferably ahydrogen atom.

Specific examples and suitable aspects of the alkyl group substitutedwith at least one fluorine atom are the same ones as the specificexamples and the suitable aspects, respectively, of Xf in GeneralFormula (3).

L represents a divalent linking group. In a case where a plurality ofeach of L's are present, L's may be the same as or different from eachother.

Examples of the divalent linking group include —COO—(—C(═O)—O—), —OCO—,—CONH—, —NHCO—, —CO—, —O—, —S—, —SO—, —SO₂—, an alkylene group(preferably having 1 to 6 carbon atoms), a cycloalkylene group(preferably having 3 to 15 carbon atoms), an alkenylene group(preferably having 2 to 6 carbon atoms), and a divalent linking groupformed by a combination of a plurality of these groups. Among these,—COO—, —OCO—, —CONH—, —NHCO—, —CO—, —O—, —SO₂—, —COO— alkylene group-,—OCO-alkylene group-, —CONH-alkylene group-, or —NHCO-alkylene group-ispreferable, and —COO—, —OCO—, —CONH—, —SO₂—, —COO-alkylene group-, or—OCO-alkylene group- is more preferable.

W represents an organic group including a cyclic structure. Among those,W is preferably a cyclic organic group.

Examples of the cyclic organic group include an alicyclic group, an arylgroup, and a heterocyclic group.

The alicyclic group may be monocyclic or polycyclic. Examples of themonocyclic alicyclic group include monocyclic cycloalkyl groups such asa cyclopentyl group, a cyclohexyl group, and a cyclooctyl group.Examples of the polycyclic alicyclic group include polycyclic cycloalkylgroups such as a norbornyl group, a tricyclodecanyl group, atetracyclodecanyl group, a tetracyclododecanyl group, and an adamantylgroup. Among those, an alicyclic group having a bulky structure having 7or more carbon atoms, such as a norbornyl group, a tricyclodecanylgroup, a tetracyclodecanyl group, a tetracyclododecanyl group, and anadamantyl group, is preferable.

The aryl group may be monocyclic or polycyclic. Examples of the arylgroup include a phenyl group, a naphthyl group, a phenanthryl group, andan anthryl group.

The heterocyclic group may be monocyclic or polycyclic. The polycycliccompound can further suppress acid diffusion. Further, the heterocyclicgroup may have aromaticity or may not have aromaticity. Examples of theheterocycle having aromaticity include a furan ring, a thiophene ring, abenzofuran ring, a benzothiophene ring, a dibenzofuran ring, adibenzothiophene ring, and a pyridine ring. Examples of the heterocyclenot having aromaticity include a tetrahydropyran ring, a lactone ring, asultone ring, and a decahydroisoquinoline ring. Examples of the lactonering and the sultone ring include the lactone structure and the sultonestructure exemplified in the aforementioned resin. As the heterocycle inthe heterocyclic group, the furan ring, the thiophene ring, the pyridinering, or the decahydroisoquinoline ring is particularly preferable.

The cyclic organic group may have a substituent. Examples of thesubstituent include an alkyl group (which may be either linear orbranched, preferably having 1 to 12 carbon atoms), a cycloalkyl group(which may be any of a monocycle, a polycycle, and a spirocycle, andpreferably has 3 to 20 carbon atoms), an aryl group (preferably having 6to 14 carbon atoms), a hydroxyl group, an alkoxy group, an ester group,an amido group, a urethane group, a ureido group, a thioether group, asulfonamido group, and a sulfonic acid ester group. Incidentally, thecarbon constituting the cyclic organic group (carbon contributing toring formation) may be carbonyl carbon.

Preferred examples of the anion represented by General Formula (3)include SO₃ ⁻—CF₂—CH₂—OCO-(L)q′-W, SO₃ ⁻—CF₂—CHF—CH₂—OCO-(L)q′-W, SO₃⁻—CF₂—COO-(L)q′-W, SO₃ ⁻—CF₂—CF₂—CH₂—CH₂-(L)q-W, or SO₃⁻—CF₂—CH(CF₃)—OCO-(L)q′-W. Here, L, q, and W are each the same as inGeneral Formula (3). q′ represents an integer of 0 to 10.

In one aspect, as Z⁻ in General Formula (ZI), Z⁻ in General Formula(ZII), Zc⁻ in General Formula (ZI-3), and Z⁻ in General Formula (ZI-4),an anion represented by General Formula (4) is also preferable.

In General Formula (4),

X^(B1) and X^(B2) each independently represent a hydrogen atom or amonovalent organic group having no fluorine atom. X^(B1) and X^(B2) areeach preferably the hydrogen atom.

X^(B3) and X^(B4) each independently represent a hydrogen atom or amonovalent organic group. It is preferable that at least one of X^(B3)or X^(B4) is a fluorine atom or a monovalent organic group having afluorine atom, and it is more preferable that both X^(B3) and X^(B4) arethe fluorine atoms or the monovalent organic groups having a fluorineatom. It is still more preferable that both X^(B3) and X^(B4) are alkylgroups substituted with a fluorine atom.

L, q, and W are the same as in General Formula (3).

Z⁻ in General Formula (ZI), Z⁻ in General Formula (ZII), Zc⁻ in GeneralFormula (ZI-3), and Z⁻ in General Formula (ZI-4) may be abenzenesulfonate anion, and are each preferably a benzenesulfonate anionsubstituted with a branched alkyl group or a cycloalkyl group.

As Z⁻ in General Formula (ZI), Z⁻ in General Formula (ZII), Zc⁻ inGeneral Formula (ZI-3), and Z⁻ in General Formula (ZI-4), an aromaticsulfonate anion represented by General Formula (SA1) is also preferable.

In Formula (SA1),

Ar represents an aryl group, and may further have a substituent otherthan a sulfonate anion and a -(D-B) group. Examples of the substituentwhich may be further contained include a fluorine atom and a hydroxylgroup.

n represents an integer of 0 or more. n is preferably 1 to 4, morepreferably 2 or 3, and still more preferably 3.

D represents a single bond or a divalent linking group. Examples of thedivalent linking group include an ether group, a thioether group, acarbonyl group, a sulfoxide group, a sulfone group, a sulfonic acidester group, an ester group, and a group consisting of a combination oftwo or more of these.

B represents a hydrocarbon group.

Preferably, D is a single bond and B is an aliphatic hydrocarbonstructure. It is more preferable that B is an isopropyl group or acyclohexyl group.

Preferred examples of the sulfonium cation in General Formula (ZI) andthe iodonium cation in General Formula (ZII) are shown below.

Preferred examples of the anion Z⁻ in each of General Formula (ZI) andGeneral Formula (ZII), Zc⁻ in General Formula (ZI-3), and Z⁻ in GeneralFormula (ZI-4) are shown below.

Any combination of the cations and the anions can be used as thephotoacid generator.

The cation or the anion may have a lactone group or a sultone group.

As the lactone group or the sultone group, any of groups having alactone structure or a sultone structure can be used, but a group havinga 5- to 7-membered ring lactone structure or a 5- to 7-membered ringsultone structure is preferable; and the group in which another ringstructure is fused to the 5- to 7-membered ring lactone structure so asto form a bicyclo structure or a spiro structure, or the group in whichanother ring structure is fused to the 5- to 7-membered ring sultonestructure so as to form a bicyclo structure or a spiro structure is morepreferable. A group having a lactone structure represented by any ofGeneral Formulae (LC1-1) to (LC1-21) or a group having a sultonestructure represented by any of General Formula (SL1-1), . . . , or(SL1-3) is more preferable. As the preferred structure, groupsrepresented by General Formula (LC1-1), General Formula (LC1-4), GeneralFormula (LC1-5), General Formula (LC1-6), General Formula (LC1-13), andGeneral Formula (LC1-14) are preferable.

The lactone structural moiety or the sultone structural moiety may havea substituent (Rb₂). Preferred examples of the substituent (Rb₂) includean alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, analkoxycarbonyl group having 1 to 8 carbon atoms, a carboxyl group, ahalogen atom, a hydroxyl group, a cyano group, and an acid-decomposablegroup. n₂ represents an integer of 0 to 4. In a case where n₂ is 2 ormore, Rb₂'s which are present in plural number may be different fromeach other and Rb₂'s which are present in plural number may be bonded toeach other to form a ring.

The pKa of an acid produced from the photoacid generator is preferablyfrom −10 to 5.

The acid dissociation constant (pKa) refers to a pKa in an aqueoussolution, and is defined in Chemical Handbook (II) (Revised 4th Edition,1993, compiled by the Chemical Society of Japan, Maruzen Company, Ltd.).A lower value of the pKa indicates higher acid strength. Specifically,the pKa in an aqueous solution can be actually measured by using aninfinite-dilution aqueous solution and measuring the acid dissociationconstant at 25° C. Alternatively, the acid dissociation constant pKa canalso be determined using the following software package 1 by computationfrom a value with respect to a Hammett substituent constant and thedatabase of publicly known literature values. Any of the values of pKadescribed in the present specification indicate values determined bycomputation using the software package.

Software Package 1: Advanced Chemistry Development (ACD/Labs) Software V8.14 for Solaris (1994-2007 ACD/Labs).

The photoacid generator may be in a form of a low-molecular-weightcompound or a form incorporated into a part of a polymer. Further, acombination of the form of a low-molecular-weight compound and the formincorporated into a part of a polymer may also be used.

The photoacid generator is preferably in the form of alow-molecular-weight compound.

In a case where the photoacid generator is in the form of alow-molecular-weight compound, the molecular weight is preferably 3,000or less, more preferably 2,000 or less, and still more preferably 1,000or less.

In a case where the photoacid generator is incorporated into a part of apolymer, it may be incorporated into a part of the resin (A) describedabove or in a resin other than the resin (A).

The photoacid generators may be used singly or in combination of two ormore kinds thereof.

Specific examples of the photoacid generator are described below, butthe present invention is not limited thereto.

The content of the photoacid generator (in a case where a plurality ofthe photoacid generators are present, a total content thereof) in thecomposition of the embodiment of the present invention is preferably0.1% to 35% by mass, more preferably 0.5% to 30% by mass, still morepreferably 1% to 30% by mass, and particularly preferably 1% to 25% bymass, with respect to a total solid content of the composition.

[Fluorine-Containing Compound Having Group Having Solubility in AlkaliDeveloper which is Increased Upon Decomposition by Action of AlkaliDeveloper]

The actinic ray-sensitive or radiation-sensitive resin composition ofthe embodiment of the present invention preferably contains afluorine-containing compound (hereinafter referred to as a“fluorine-containing compound (C)”) having a group having a solubilityin an alkali developer which is increased upon decomposition by theaction of the alkali developer.

The fluorine-containing compound (C) can be unevenly distributed on asurface of the actinic ray-sensitive or radiation-sensitive film of theembodiment of the present invention by containing fluorine, whereby itcan exhibit desired performance.

The group having a solubility in an alkali developer which is increasedupon decomposition by the action of the alkali developer is alsoreferred to as a “polarity conversion group”, and specific examplesthereof include a lactone group, a carboxylic acid ester group (—COO—),an acid anhydride group (—C(O)OC(O)—), an acid imido group (—NHCONH—), acarboxylic acid thioester group (—COS—), a carbonic acid ester group(—OC(O)O—), a sulfuric acid ester group (—OSO₂O—), and a sulfonic acidester group (—SO₂O—).

Furthermore, the ester group directly linked to the main chain of therepeating unit, in the same manner as those in acrylate and the like, isdeteriorated in a function of increasing a solubility in an alkalideveloper upon decomposition by the action of the alkali developer, andtherefore, such the ester group is not included in the polarityconversion group in the present invention.

The fluorine-containing compound (C) preferably has a fluoroalkyl groupfrom the viewpoint of surface uneven distribution.

The fluorine-containing compound (C) is more preferably a resin (alsoreferred to as a “resin (C)”).

The fluorine-containing compound (C) is more preferably a resinincluding a repeating unit having a polarity conversion group (alsoreferred to as a “repeating unit (c)”).

Examples of the repeating unit (c) include a repeating unit representedby General Formula (K0).

In General Formula (KO), R_(k1) represents a hydrogen atom, a halogenatom, a hydroxyl group, an alkyl group, a cycloalkyl group, an arylgroup, or a group including a polarity conversion group.

R_(k2) represents an alkyl group, a cycloalkyl group, an aryl group, ora group including a polarity conversion group.

It should be noted that at least one of R_(k1) or R_(k2) has a polarityconversion group. In addition, the ester group directly linked to themain chain of the repeating unit represented by General Formula (K0) isnot included in the polarity conversion group in the present invention,as described above.

The polarity conversion group is preferably a group represented by X ina partial structure represented by General Formula (KA-1) or (KB-1).

That is, it is preferable that the repeating unit (c) has at least onepartial structure represented by General Formula (KA-1) or (KB-1), andthe polarity conversion group is represented by X in the partialstructure represented by has General Formula (KA-1) or (KB-1).

X in General Formula (KA-1) or (KB-1) represents a carboxylic acid estergroup: —COO—, an acid anhydride group: —C(O)OC(O)—, an acid imido group:—NHCONH—, a carboxylic acid thioester group: —COS—, a carbonic acidester group: —OC(O)O—, a sulfuric acid ester group: —OSO₂O—, and asulfonic acid ester group: —SO₂O—.

Y¹ and Y² may be the same as or different from each other, and eachrepresent an electron-withdrawing group.

In addition, the repeating unit (c) has a group having the partialstructure represented by General Formula (KA-1) or (KB-1), and thus hasa preferred polarity conversion group, but in a case where the partialstructure does not have a bond, such as a case of the partial structurerepresented by General Formula (KA-1) and the partial structurerepresented by General Formula (KA-B) in which Y¹ and Y² are monovalent,the group having the partial structure is a group having a monovalent orhigher-valent group obtained by removing at least any one hydrogen atomin the partial structure.

The partial structure represented by General Formula (KA-1) or (KB-1) islinked to the main chain of the resin (C) via a substituent at anyposition.

The partial structure represented by General Formula (KA-1) is astructure that forms a ring structure together with the group as X.

As X in General Formula (KA-1), a carboxylic acid ester group (that is,in a case of forming a lactone ring structure as KA-1), an acidanhydride group, or a carbonic acid ester group is preferable. Thecarboxylic acid ester group is more preferable.

The ring structure represented by General Formula (KA-1) may have asubstituent, and for example, may have nka substituents Z_(ka1).

In a case where a plurality of Z_(ka1)'s are present, Z_(ka1)'s eachindependently represent an alkyl group, a cycloalkyl group, an ethergroup, a hydroxyl group, an amido group, an aryl group, a lactone ringgroup, or an electron-withdrawing group.

Z_(ka1)'s may be linked to each other to form a ring. Examples of thering formed by the mutual linkage of Z_(ka1)'s include a cycloalkyl ringand a heterocycle (a cyclic ether ring, a lactone ring, and the like).

nka represents an integer of 0 to 10. nka is preferably an integer of 0to 8, more preferably an integer of 0 to 5, still more preferably aninteger of 1 to 4, and most preferably an integer of 1 to 3.

The electron-withdrawing group as Z_(ka1) is the same as theelectron-withdrawing group as each of Y¹ and Y² which will be describedlater, typified by a halogen atom.

In addition, the electron-withdrawing group may be substituted withanother electron-withdrawing group.

Z_(ka1) is preferably the alkyl group, the cycloalkyl group, the ethergroup, the hydroxyl group, or the electron-withdrawing group, and morepreferably the alkyl group, the cycloalkyl group, or theelectron-withdrawing group. In addition, the ether group is preferablyan ether group substituted with an alkyl group, a cycloalkyl group, orthe like, that is, an alkyl ether group or the like. Preferred examplesof the electron-withdrawing group are the same ones as theelectron-withdrawing group as each of Y¹ and Y² which will be describedlater.

Examples of the halogen atom as Z_(ka1) include a fluorine atom, achlorine atom, a bromine atom, and an iodine atom, and the fluorine atomis preferable.

The alkyl group as Z_(ka1) may have a substituent and may be eitherlinear or branched. The linear alkyl group preferably has 1 to 30 carbonatoms, and more preferably has 1 to 20 carbon atoms, and examplesthereof include a methyl group, an ethyl group, an n-propyl group, ann-butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, ann-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group,and an n-decanyl group. The branched alkyl group preferably has 3 to 30carbon atoms, and more preferably has 3 to 20 carbon atoms, and examplesthereof include an i-propyl group, an i-butyl group, a t-butyl group, ani-pentyl group, a t-pentyl group, an i-hexyl group, a t-hexyl group, ani-heptyl group, a t-heptyl group, an i-octyl group, a t-octyl group, ani-nonyl group, and a t-decanoyl group. The alkyl groups having 1 to 4carbon atoms, such as a methyl group, an ethyl group, an n-propyl group,an i-propyl group, an n-butyl group, an i-butyl group, and a t-butylgroup, are preferable.

The cycloalkyl group as Z_(ka1) may have a substituent, may bemonocyclic or polycyclic, and may also be bridged. For example, thecycloalkyl group may have a bridged structure. As the monocyclic group,a cycloalkyl group having 3 to 8 carbon atoms is preferable, andexamples thereof include a cyclopropyl group, a cyclopentyl group, acyclohexyl group, a cyclobutyl group, and a cyclooctyl group. Examplesof the polycyclic group include a cycloalkyl group having 5 or morecarbon atoms, having a bicyclo, tricyclo, or tetracyclo structure, orthe like, cycloalkyl groups having 6 to 20 carbon atoms are preferable,and examples thereof include an adamantyl group, a norbornyl group, anisobornyl group, a camphanyl group, a dicyclopentyl group, an α-pinelgroup, a tricyclodecanyl group, a tetracyclododecyl group, and anandrostanyl group. The following structure is also preferable as thecycloalkyl group. In addition, some of the carbon atoms in thecycloalkyl group may be substituted with heteroatoms such as an oxygenatom.

Preferred examples of the alicyclic moiety include an adamantyl group, anoradamantyl group, a decalin group, a tricyclodecanyl group, atetracyclododecanyl group, a norbornyl group, a cedrol group, acyclohexyl group, a cycloheptyl group, a cyclooctyl group, acyclodecanyl group, and a cyclododecanyl group. More preferred are theadamantyl group, the decalin group, the norbornyl group, the cedrolgroup, the cyclohexyl group, the cycloheptyl group, the cyclooctylgroup, the cyclodecanyl group, the cyclododecanyl group, and thetricyclodecanyl group.

Examples of a substituent having the alicyclic structure include analkyl group, a halogen atom, a hydroxyl group, an alkoxy group, acarboxyl group, and an alkoxycarbonyl group. As the alkyl group, a loweralkyl group such as a methyl group, an ethyl group, a propyl group, anisopropyl group, and a butyl group is preferable, and the methyl group,the ethyl group, the propyl group, or the isopropyl group is morepreferable. As the alkoxy group, those having 1 to 4 carbon atoms, suchas a methoxy group, an ethoxy group, a propoxy group, and a butoxygroup, are preferable. Examples of a substituent which may be containedin the alkyl group and the alkoxy group include a hydroxyl group, ahalogen atom, and an alkoxy group (preferably having 1 to 4 carbonatoms).

Examples of the lactone ring group of Z_(ka1) include groups obtained byremoving a hydrogen atom from a structure represented by any of (KA-1-1)to (KA-1-17) which will be described later.

Examples of the aryl group of Z_(ka1) include a phenyl group and anaphthyl group.

Examples of the substituent which may further be contained in the alkylgroup, the cycloalkyl group, or the aryl group of Z_(ka1) include ahydroxyl group, a halogen atom (fluorine, chlorine, bromine, andiodine), a nitro group, a cyano group, an alkyl group, an alkoxy groupsuch as a methoxy group, an ethoxy group, a hydroxyethoxy group, apropoxy group, a hydroxypropoxy group, an n-butoxy group, an isobutoxygroup, a sec-butoxy group, and a t-butoxy group, an alkoxycarbonyl groupsuch as a methoxycarbonyl group and an ethoxycarbonyl group, an aralkylgroup such as a benzyl group, a phenethyl group, and a cumyl group, anaralkyloxy group, an acyl group such as a formyl group, an acetyl group,a butyryl group, a benzoyl group, a cyanamyl group, and a valeryl group,an acyloxy group such as a butyryloxy group, the alkenyl group, analkenyloxy group such as a vinyloxy group, a propenyloxy group, anallyloxy group, and a butenyloxy group, an aryl group, an aryloxy groupsuch as a phenoxy group, and an aryloxycarbonyl group such as abenzoyloxy group.

It is preferable that X in General Formula (KA-1) is the carboxylic acidester group and the partial structure represented by General Formula(KA-1) is the lactone ring, and preferably a 5- to 7-membered lactonering.

In addition, as in (KA-1-1) to (KA-1-17), it is preferable that anotherring structure is fused to the 5- to 7-membered lactone ring as thepartial structure represented by General Formula (KA-1) to form abicyclo structure or a spiro structure.

Examples of the peripheral ring structure to which the ring structurerepresented by General Formula (KA-1) may be bonded include the ringsfor (KA-1-1) to (KA-1-17), or a ring equivalent thereto.

As a structure containing the lactone ring structure represented byGeneral Formula (KA-1), the structures represented by any of (KA-1-1) to(KA-1-17) are more preferable. Further, the lactone structure may bedirectly bonded to the main chain. Preferred examples of the structureinclude (KA-1-1), (KA-1-4), (KA-1-5), (KA-1-6), (KA-1-13), (KA-1-14),and (KA-1-17).

The structure containing the lactone ring structure may or may not havea substituent. Preferred examples of the substituent include the sameones as the substituents which may be contained in the ring structurerepresented by General Formula (KA-1).

The lactone structure may have an optically active substance, but any ofoptically active substances may be used. In addition, one kind ofoptically active substances may be used singly or a plurality of kindsof optically active substances may be mixed and used. In a case whereone kind of optically active substance is mainly used, an optical purity(ee) thereof is preferably 90% or more, more preferably 95% or more, andmost preferably 98% or more.

Preferred examples of X in General Formula (KB-1) include a carboxylicacid ester group (—COO—).

Y¹ and Y² in General Formula (KB-1) each independently represent anelectron-withdrawing group.

The electron-withdrawing group is preferably a partial structurerepresented by Formula (EW). In Formula (EW), * represents a bonddirectly linked to (KA-1) or a bond directly linked to X in (KB-1).

In Formula (EW),

n_(ew) is a repetition number of the linking groups represented by—C(R_(ew1))(R_(ew2))— and represents an integer of 0 or 1. In a casewhere n_(ew) is 0, this indicates that the bonding is formed by a singlebond and Y_(ew1) is directly bonded.

Y_(ew1) is a halogen atom, a cyano group, a nitrile group, a nitrogroup, a halo(cyclo)alkyl group or haloaryl group represented by—C(R_(f1))(R_(f2))—R_(f3), an oxy group, a carbonyl group, a sulfonylgroup, a sulfinyl group, or a combination thereof, and theelectron-withdrawing group may be, for example, the following structure.In addition, the “halo(cyclo)alkyl group” represents an alkyl orcycloalkyl group which is at least partially halogenated. R_(ew3) andR_(ew4) each independently represent any structure. R_(ew3) and R_(ew4)may have any structure, and the partial structure represented by Formula(EW) has an electron-withdrawing property, and may be linked, forexample, to the main chain of the resin but is preferably an alkylgroup, a cycloalkyl group, or a fluorinated alkyl group.

In a case where Y_(ew1) is a divalent or higher-valent group, theremaining bond forms a bond with any atom or substituent. At least anyone group of Y_(ew1), R_(ew1), and R_(ew2) may be linked to the mainchain of the resin (C) via a further substituent.

Y_(ew1) is preferably a halogen atom, or a halo(cyclo)alkyl group orhaloaryl group represented by —C(R_(f1))(R_(f2))—R_(f3).

R_(ew1) and R_(ew2) each independently represent any substituent, forexample, a hydrogen atom, an alkyl group, a cycloalkyl group, or an arylgroup.

At least two of R_(ew1), R_(ew2), or Y_(ew1) may be linked to each otherto form a ring.

Here, R_(f1) represents a halogen atom, a perhaloalkyl group, aperhalocycloalkyl group, or a perhaloaryl group, more preferablyrepresents a fluorine atom, the perfluoroalkyl group, or theperfluorocycloalkyl group, and still more preferably represents thefluorine atom or a trifluoromethyl group.

R_(f2) and R_(f3) each independently represent a hydrogen atom, ahalogen atom, or an organic group, and R_(f2) and R_(f3) may be linkedto each other to form a ring. Examples of the organic group include analkyl group, a cycloalkyl group, and an alkoxy group, and these may besubstituted with a halogen atom (preferably a fluorine atom), and R_(f2)and R_(f3) are more preferably (halo)alkyl groups. It is more preferablethat R_(f2) represents the same group as R_(f1) or is linked to R_(f3)to form a ring.

R_(f1) and R_(f3) may be linked to form a ring, and examples of the ringformed include a (halo)cycloalkyl ring and a (halo)aryl ring.

Examples of the (halo)alkyl group in R_(f1) to R_(f3) include the alkylgroup for Z_(ka1) described above and a halogenated structure thereof.

Examples of the (per)halocycloalkyl group and the (per)haloaryl group ineach of R_(f1) to R_(f3) or in the ring formed by the linkage betweenR_(f2) and R_(f3) include structures resulting from halogenation of thecycloalkyl groups in Z_(ka1), and a fluorocycloalkyl group representedby —C_((n))F_((2n−2))H and a perfluoroaryl group represented by—C_((n))F_((n−1)). Here, the number n of carbon atoms is notparticularly limited, but is preferably 5 to 13, and more preferably 6.

Preferred examples of a ring which may be formed by the mutual linkageof at least two of R_(ew1), R_(ew2), or Y_(ew1) include a cycloalkylgroup and a heterocyclic group, and as the heterocyclic group, a lactonering group is preferable. Examples of the lactone ring include thestructures represented by Formulae (KA-1-1) to (KA-1-17).

Moreover, the repeating unit (c) may have a plurality of the partialstructures represented by General Formula (KA-1), a plurality of thepartial structures represented by General Formula (KB-1), or both thepartial structures of General Formula (KA-1) and General Formula (KB-1).

Furthermore, a part or a whole of the partial structure of GeneralFormula (KA-1) may also serve as the electron-withdrawing group as Y¹ orY² in General Formula (KB-1). For example, in a case where X in GeneralFormula (KA-1) is a carboxylic acid ester group, the carboxylic acidester group can function as an electron-withdrawing group as Y¹ or Y² inGeneral Formula (KB-1).

The repeating unit (c) may be any of a repeating unit (c′) having afluorine atom and a polarity conversion group on one side chain; arepeating unit (c*) having a polarity conversion group but not having afluorine atom; and a repeating unit (c″) having a polarity conversiongroup on one side chain and having a fluorine atom on a side chaindifferent from the side chain in the same repeating unit; however, it ismore preferable that the resin (C) has the repeating unit (c′) as therepeating unit (c). That is, it is more preferable that the repeatingunit (c) having at least one polarity conversion group has a fluorineatom.

In addition, in a case where the resin (C) has the repeating unit (c*),it is preferably a copolymer with a repeating unit having a fluorineatom (a repeating unit (c1) which will be described later). Further, itis preferable that the side chain having a polarity conversion group andthe side chain having a fluorine atom in the repeating unit (c″) arebonded to the same carbon atom in the main chain, that is, the sidechains are in a positional relationship as in Formula (K1).

In the formula, B1 represents a partial structure having a polarityconversion group and B2 represents a partial structure having a fluorineatom.

Moreover, in the repeating unit (c*) and the repeating unit (c″), thepolarity conversion group is more preferably a partial structurerepresented by —COO— in the structure represented by General Formula(KA-1).

The hydrolysis rate of the resin (C) with respect to an alkali developeris preferably 0.001 nm/sec or more, more preferably 0.01 nm/sec or more,still more preferably 0.1 nm/sec or more, and most preferably 1 nm/secor more.

Here, the hydrolysis rate of the resin (C) with respect to the alkalideveloper refers to a rate of a decrease in the thickness of a resinfilm formed only of the resin (C) in an aqueous tetramethylammoniumhydroxide (TMAH) solution (2.38%-by-mass) at 23° C.

The resin (C) of the present invention is preferably a resin (C1) whichcontains a repeating unit (c) having at least two or more polarityconversion groups and has a fluorine atom.

In a case where the repeating unit (c) has at least two polarityconversion groups, it is preferable that the repeating unit (c) has apartial structure having two polarity conversion groups, represented byGeneral Formula (KY-1). In addition, in a case where the structurerepresented by General Formula (KY-1) does not have a bond, it is amonovalent or higher-valent group obtained by removing at least any onehydrogen atom in the structure.

In General Formula (KY-1),

R_(ky1) and R_(ky4) each independently represent a hydrogen atom, ahalogen atom, an alkyl group, a cycloalkyl group, a carbonyl group, acarbonyloxy group, an oxycarbonyl group, an ether group, a hydroxylgroup, a cyano group, an amido group, or an aryl group. Alternatively,R_(ky1) and R_(ky4) may be bonded to the same atom to form a doublebond, and for example, R_(ky1) and R_(ky4) may be bonded to the sameoxygen atom to form a part of a carbonyl group (═O).

R_(ky2) and R_(ky3) are each independently an electron-withdrawinggroup, or R_(ky1) and R_(ky2) are linked to each other to form a lactonering and R_(ky3) is an electron-withdrawing group. As the lactone ringto be formed, the structures of (KA-1-1) to (KA-1-17) are preferable.Examples of the electron-withdrawing group include the same ones asthose of Y¹ and Y² in Formula (KB-1), and the electron-withdrawing groupis preferably a halogen atom, or a halo(cyclo)alkyl group or haloarylgroup represented by —C(R_(f1))(R_(f2))—R_(f3). Preferably, R_(ky3) is ahalogen atom, or a halo(cyclo)alkyl group or haloaryl group representedby —C(R_(f1))(R_(f2))—R_(f3), and R_(ky2) is linked to R_(ky1) to form alactone ring or is an electron-withdrawing group having no halogen atom.

R_(ky1), R_(ky2), and R_(ky4) may be linked to each other to form amonocyclic or polycyclic structure.

Specific examples of R_(ky1) and R_(ky4) include the same groups asZ_(ka1) in Formula (KA-1).

As the lactone ring formed by the linkage of R_(ky1) and R_(ky2), thestructures (KA-1-1) to (KA-1-17) are preferable. Examples of theelectron-withdrawing group include the same ones as those of Y¹ and Y²in Formula (KB-1).

The structure represented by General Formula (KY-1) is more preferably astructure represented by General Formula (KY-2). Further, the structurerepresented by General Formula (KY-2) is a monovalent or higher-valentgroup obtained by removing at least one of any hydrogen atoms in thestructure.

In Formula (KY-2),

R_(ky6) to Rky₁₀ each independently represent a hydrogen atom, a halogenatom, an alkyl group, a cycloalkyl group, a carbonyl group, acarbonyloxy group, an oxycarbonyl group, an ether group, a hydroxylgroup, a cyano group, an amido group, or an aryl group.

Two or more of R_(ky6), . . . , or R_(ky10) may be linked to each otherto form a monocyclic or polycyclic structure.

R_(ky5) represents an electron-withdrawing group. Examples of theelectron-withdrawing group include the same ones as those in Y¹ and Y²,and the electron-withdrawing group is preferably a halogen atom, or ahalo(cyclo)alkyl group or haloaryl group represented by—C(R_(f1))(R_(f2))—R_(f3).

Specific examples of R_(ky5) to R_(ky10) include the same ones as thoseas Z_(ka1) in Formula (KA-1).

The structure represented by Formula (KY-2) is more preferably a partialstructure represented by General Formula (KY-3).

In Formula (KY-3),

Z_(ka1) and nka each have the same definitions as in General Formula(KA-1). R_(ky5) has the same definition as in Formula (KY-2).

L_(ky) represents an alkylene group, an oxygen atom, or a sulfur atom.Examples of the alkylene group of L_(ky) include a methylene group andan ethylene group. L_(ky) is preferably the oxygen atom or the methylenegroup, and more preferably the methylene group.

The repeating unit (c) is not limited as long as it is a repeating unitobtained by polymerization such as addition polymerization, condensationpolymerization, and addition condensation, but is preferably a repeatingunit obtained by addition polymerization of carbon-carbon double bonds.Examples of the repeating unit (c) include an acrylate-based repeatingunit (including a system having a substituent at the α- or β-position),a styrene-based repeating unit (including a system having a substituentat the α- or β-position), a vinyl ether-based repeating unit, anorbornene-based repeating unit, and a maleic acid derivative (maleicacid anhydride or a derivative thereof, maleimide, and the like)repeating unit; and the acrylate-based repeating unit, the styrene-basedrepeating unit, the vinyl ether-based repeating unit, or thenorbornene-based repeating unit is preferable, the acrylate-basedrepeating unit, the vinyl ether-based repeating unit, or thenorbornene-based repeating unit is more preferable, and theacrylate-based repeating unit is most preferable.

As a more specific structure of the repeating unit (c), a repeating unithaving a partial structure shown below is preferable.

The repeating unit (c) can be a repeating unit having a partialstructure shown below.

In General Formula (cc),

In a case where a plurality of Z₁'s are present, Z₁'s each independentlyrepresent a single bond, an ether bond, an ester bond, an amide bond, aurethane bond, or a urea bond, and preferably represent the ester bond.

In a case where a plurality of Z₂'s are present, Z₂'s each independentlyrepresent a chain or cyclic alkylene group, and preferably represent analkylene group having 1 or 2 carbon atoms or a cycloalkylene grouphaving 5 to 10 carbon atoms.

Ta's each independently represent an alkyl group, a cycloalkyl group, analkoxy group, a nitrile group, a hydroxyl group, an amido group, an arylgroup, or an electron-withdrawing group (having the same definition asthat of the electron-withdrawing group as each of Y¹ and Y² in GeneralFormula (KB-1)), preferably represent the alkyl group, the cycloalkylgroup, or the electron-withdrawing group, and more preferably representthe electron-withdrawing group. In a case where a plurality of Ta's arepresent, Ta's may be bonded to each other to form a ring.

L₀ represents a single bond or an m+1-valent hydrocarbon group(preferably having 20 or less carbon atoms), and preferably represents asingle bond. The single bond as L₀ corresponds to a case where m is 1.The m+1-valent hydrocarbon group as L₀ represents, for example, analkylene group, a cycloalkylene group, a phenylene group, or am+1-valent hydrocarbon group obtained by removing any m−1 hydrogen atomsfrom a combination of those groups.

L's each independently represent a carbonyl group, a carbonyloxy group,or an ether group.

Tc is a hydrogen atom, an alkyl group, a cycloalkyl group, a nitrilegroup, a hydroxyl group, an amido group, an aryl group, or anelectron-withdrawing group (having the same definition as that of theelectron-withdrawing group as each of Y¹ and Y² in General Formula(KB-1)).

* represents a bond to the main chain or a side chain of the resin. Thatis, the partial structure represented by Formula (cc) may be directlylinked to the main chain, and the partial structure represented byFormula (cc) may be bonded to the side chain of the resin. Further, thebond to the main chain is a bond to an atom which exists in a bondconstituting the main chain, and the bond to a side chain is a bond toan atom which exists in a part other than a bond constituting the mainchain.

m represents an integer of 1 or 28, and is preferably an integer of 1 to3, and more preferably 1.

k represents an integer of 0 to 2, and is preferably 1.

q represents a repetition number of the groups (Z₂-Z₁), represents aninteger of 0 to 5, and is preferably 0 to 2.

r represents an integer of 0 to 5.

In addition, -(L)r-Tc may be substituted with -L₀-(Ta)m.

A case where a sugar lactone has a fluorine atom at a terminal thereofand a case where the sugar lactone has a fluorine atom on a side chaindifferent from the side chain on the sugar lactone side in the samerepeating unit (repeating unit (c″)) are also preferable.

In a case where the chain alkylene group as Z₂ is a linear alkylenegroup, it preferably has 1 to 30 carbon atoms, and more preferably has 1to 20 carbon atoms; and in a case where the chain alkylene group is abranched alkylene group, it preferably has 3 to 30 carbon atoms, andmore preferably has 3 to 20 carbon atoms. Specific examples of the chainalkylene group as R₂ include a group obtained by removing one of anyhydrogen atoms from the specific examples of the alkyl group as Z_(ka1).

The cyclic alkylene group as Z₂ preferably has 3 to 8 carbon atoms, andspecific examples thereof include a group obtained by removing one ofany hydrogen atoms from the cycloalkyl group as Z_(ka1).

The preferred number of carbon atoms and preferred specific examples ofthe alkyl group and cycloalkyl group as each of Ta and Tc are each thesame ones as those described for the alkyl group and the cycloalkylgroup as Z_(ka1).

The alkoxy group as Ta preferably has 1 to 8 carbon atoms, and examplesthereof include a methoxy group, an ethoxy group, a propoxy group, and abutoxy group.

Preferred examples of the aryl group as each of Ta and Tc include anaryl group having 6 to 12 carbon atoms, for example, a phenyl group anda naphthyl group.

The preferred number of carbon atoms and preferred specific examples ofthe alkylene group and cycloalkylene group as L₀ are each the same onesas those described for the chain alkylene group and the cyclic alkylenegroup as Z₂.

As a more specific structure of the repeating unit (c), a repeating unithaving a partial structure shown below is preferable.

In General Formulae (ca-2) and (cb-2),

n represents an integer of 0 to 11, preferably represents an integer of0 to 5, and more preferably represents 1 or 2.

p represents an integer of 0 to 5, preferably represents an integer of 0to 3, and more preferably represents 1 or 2.

Tb's independently represent an alkyl group, a cycloalkyl group, analkoxy group, a nitrile group, a hydroxyl group, an amido group, an arylgroup, or an electron-withdrawing group (having the same definition asthat of the electron-withdrawing group as each of Y¹ and Y² in GeneralFormula (KB-1)), and preferably represent the alkyl group, thecycloalkyl group, or the electron-withdrawing group. In a case wherethere are a plurality of Tb's, Tb's may be bonded to each other to forma ring.

* represents a bond to the main chain or a side chain of the resin. Thatis, the partial structure represented by Formula (ca-2) or (cb-2) may bedirectly linked to the main chain, or the partial structure representedby Formula (ca-2) or (cb-2) may be bonded to the side chain of theresin.

Z₁, Z₂, Ta, Tc, L, *, m, q, and r have the same definitions as inGeneral Formula (cc), and preferred ones are also the same.

In General Formula (KY-4),

R₂ represents a chain or cyclic alkylene group, and in a case where aplurality of R₂'s are present, R₂'s may be the same as or different fromeach other.

R₃ represents a linear, branched, or cyclic hydrocarbon group in whichsome or all of the hydrogen atoms on the constituent carbon aresubstituted with fluorine atoms.

R₄ represents a halogen atom, a cyano group, a hydroxy group, an amidogroup, an alkyl group, a cycloalkyl group, an alkoxy group, a phenylgroup, an acyl group, an alkoxycarbonyl group, or a group represented byR—C(═O)— or R—C(═O)O— (R represents an alkyl group or a cycloalkylgroup). In a case where a plurality of R₄'s are present, R₄'s may be thesame as or different from each other, and two or more R₄'s may be bondedto each other to form a ring.

X represents an alkylene group, an oxygen atom, or a sulfur atom.

In a case where a plurality of each of Z's and Za's are present, Z's andZa's each independently represent a single bond, an ether bond, an esterbond, an amide bond, a urethane bond, or a urea bond, and in a casewhere a plurality of Z's and Za's are present, Z's and Za's may be eachthe same as or different from each other.

* represents a bond to the main chain or a side chain of the resin.

o is the number of substituents and represents an integer of 1 to 7.

m is the number of substituents and represents an integer of 0 to 7.

n represents the repetition number and represents an integer of 0 to 5.

As the structure of —R₂—Z—, a structure represented by —(CH₂)_(l)—COO—is preferable (1 represents an integer of 1 to 5).

The preferred number of carbon atoms and preferred specific examples ofthe chain or cyclic alkylene group as R₂ are each the same ones as thosedescribed for the chain alkylene group and the cyclic alkylene group forZ₂ in General Formula (cc).

With regard to the number of carbon atoms of the linear, branched, orcyclic hydrocarbon group as R₃, in a c case where R₃ is a linearhydrocarbon group, the number of carbon atoms is preferably 1 to 30, andmore preferably 1 to 20; in a case where R₃ is a branched hydrocarbongroup, the number of carbon atoms is preferably 3 to 30, and morepreferably 3 to 20; and in a case where R₃ is a cyclic hydrocarbongroup, the number of carbon atoms is 6 to 20. Specific examples of R₃include the specific examples of the alkyl group and the cycloalkylgroup as Z_(ka1) described above.

The preferred number of carbon atoms and preferred specific examples ofthe alkyl group and the cycloalkyl group as each of R₄ and R are eachthe same ones as those described for the alkyl group and the cycloalkylgroup as Z_(ka1) described above.

The acyl group as R₄ preferably has 1 to 6 carbon atoms, and examplesthereof include a formyl group, an acetyl group, a propionyl group, abutyryl group, an isobutyryl group, a valeryl group, and a pivaloylgroup.

Examples of the alkyl moiety in each of the alkoxy group and thealkoxycarbonyl group as R₄ include a linear, branched, or cyclic alkylmoiety, and the preferred number of carbon atoms and specific examplesof the alkyl moiety are each the same ones as those described for thealkyl group and the cycloalkyl group as Z_(ka1).

Examples of the alkylene group as X include a chain or cyclic alkylenegroup, and the preferred number of carbon atoms and specific example ofthe alkylene group are each the same ones as those described for thechain alkylene group and the cyclic alkylene group as R₂.

A repeating unit having a partial structure represented by GeneralFormula (KY-5) is more preferable.

In General Formula (KY-5),

R₂ represents a chain or cyclic alkylene group, and in a case where aplurality of R₂'s are present, R₂'s may be the same as or different fromeach other.

R₃ represents a linear, branched, or cyclic hydrocarbon group in whichsome or all of the hydrogen atoms on the constituent carbon aresubstituted with fluorine atoms.

R₄ represents a halogen atom, a cyano group, a hydroxy group, an amidogroup, an alkyl group, a cycloalkyl group, an alkoxy group, a phenylgroup, an acyl group, an alkoxycarbonyl group, or a group represented byR—C(═O)— or R—C(═O)O— (R represents an alkyl group or a cycloalkylgroup). In a case where there are a plurality of R₄'s, R₄'s may be thesame as or different from each other, and two or more R₄'s may be bondedto each other to form a ring.

X represents an alkylene group, an oxygen atom, or a sulfur atom.

Z represents a single bond, an ether bond, an ester bond, an amide bond,a urethane bond, or a urea bond, and in a case where a plurality of Z'sare present, Z's may be the same as or different from each other.

* represents a bond to the main chain or a side chain of the resin.

n represents the repetition number and represents an integer of 0 to 5.

m is the number of substituents and represents an integer of 0 to 7.

The preferable range and specific examples of the number of carbon atomsfor each of R₂ to R₄ and X are the same ones as those described inGeneral Formula (KY-4).

As the structure of —R₂—Z—, a structure represented by —(CH₂)_(l)—COO—is preferable (1 represents an integer of 1 to 5).

In General Formulae (rf-1) and (rf-2),

X′ represents an electron-withdrawing substituent, and is preferably acarbonyloxy group, an oxycarbonyl group, an alkylene group substitutedwith a fluorine atom, or a cycloalkylene group substituted with afluorine atom.

A represents a single bond or a divalent linking group represented by—C(Rx)(Ry)-. Here, Rx and Ry each independently represent a hydrogenatom, a fluorine atom, an alkyl group (which preferably has 1 to 6carbon atoms and may be substituted with a fluorine atom or the like),or a cycloalkyl group (which preferably has 5 to 12 carbon atoms and maybe substituted with a fluorine atom or the like). Rx and Ry arepreferably the hydrogen atom, the alkyl group, or the alkyl groupsubstituted with a fluorine atom.

X represents an electron-withdrawing group, and is preferably afluorinated alkyl group, a fluorinated cycloalkyl group, an aryl groupsubstituted with fluorine or a fluorinated alkyl group, an aralkyl groupsubstituted with fluorine or a fluorinated alkyl group.

* represents a bond to the main chain or a side chain of the resin. Thatis, * represents a bond which bonds to the main chain of the resinthrough a single bond or a linking group.

In addition, in a case where X is a carbonyloxy group or an oxycarbonylgroup, A is not a single bond.

In a case where the alkylene group in the alkylene group substitutedwith a fluorine atom as X′ is a linear alkylene group, it preferably has1 to 30 carbon atoms, and has more preferably 1 to 20 carbon atoms, andin a case where the alkylene group is a branched alkylene group, itpreferably 3 to 30 carbon atoms, and more preferably has 3 to 20 carbonatoms. Specific examples of the alkylene group include groups obtainedby removing any one hydrogen atom from the specific examples of thealkyl group as Z_(ka1) described above. The alkylene group substitutedwith a fluorine atom is preferably a perfluoroalkylene group.

The cycloalkylene group in the cycloalkylene group substituted with afluorine atom as X′ preferably has 3 to 8 carbon atoms, and specificexamples thereof include a group obtained by removing any one hydrogenatom from the specific examples of the cycloalkyl group as Z_(ka1). Thecycloalkylene group substituted with a fluorine atom is preferably aperfluorocycloalkylene group.

In a case where the alkyl group in the fluorinated alkyl group as X is alinear alkyl group, it preferably has 1 to 30 carbon atoms, and morepreferably 1 to 20 carbon atoms; and in a case where the alkyl group isa branched alkyl group, it preferably has 3 to 30 carbon atoms, and morepreferably has 3 to 20 carbon atoms. Specific examples of the alkylgroup include the specific examples of the alkyl group as Z_(ka1)described above. The fluorinated alkyl group is preferably aperfluoroalkyl group.

The cycloalkyl group in the fluorinated cycloalkyl group as X preferablyhas 3 to 8 carbon atoms, and specific examples thereof include thespecific examples of the cycloalkyl group as Z_(ka1). The fluorinatedcycloalkyl group is preferably a perfluorocycloalkyl group.

The aryl group in the aryl group substituted with fluorine or afluorinated alkyl group as X is preferably an aryl group having 6 to 12carbon atoms, for example, a phenyl group and a naphthyl group. Further,specific examples of the fluorinated alkyl group in the aryl groupsubstituted with a fluorinated alkyl group are the same ones as thosedescribed for the fluorinated alkyl group as X.

Preferred examples of the aralkyl group in the aralkyl group substitutedwith fluorine or a fluorinated alkyl group as X include an aralkyl grouphaving 6 to 12 carbon atoms, for example, a benzyl group, a phenethylgroup, a naphthylmethyl group, a naphthylethyl group, and anaphthylbutyl group. Further, specific examples of the fluorinated alkylgroup in the aralkyl group substituted with a fluorinated alkyl groupare the same ones as those described for the fluorinated alkyl group asX.

The resin (C) preferably has a repeating unit represented by GeneralFormula (2) as the repeating unit (c).

In General Formula (2), R₂₁ represents a hydrogen atom or a monovalentorganic group. X₂ represents a divalent linking group. R₂₂ and R₂₃ eachindependently represent a fluoroalkyl group. R₂₄ represents a hydrogenatom, a fluorine atom, or a monovalent organic group.

As the divalent linking group represented by X₂ in General Formula (2),a divalent linking group having the above-mentioned polarity conversiongroup is preferable, and a divalent linking group having a lactonestructure is particularly preferable.

In General Formula (2), R₂₁ preferably represents a hydrogen atom or analkyl group, and more preferably represents the hydrogen atom or analkyl group having 1 to 5 carbon atoms.

In General Formula (2), R₂₂ and R₂₃ each independently represent afluoroalkyl group, preferably represent a fluoroalkyl group having 1 to10 carbon atoms, and more preferably represent a fluoroalkyl grouphaving 1 to 5 carbon atoms.

In General Formula (2), R₂₄ preferably represents a hydrogen atom, afluorine atom, or a fluoroalkyl group having 1 to 10 carbon atoms, andmore preferably represents the hydrogen atom, the fluorine atom, or afluoroalkyl group having 1 to 5 carbon atoms.

Specific examples of the repeating unit (c) having a polarity conversiongroup are shown below, but the present invention is not limited thereto.

Ra represents a hydrogen atom, a fluorine atom, a methyl group, or atrifluoromethyl group.

The content of the repeating unit (c) in the resin (C) is preferably 10%to 100% by mole, more preferably 20% to 100% by mole, still morepreferably 30% to 100% by mole, and most preferably 40% to 100% by mole,with respect to all the repeating units in the resin (C).

The content of the repeating unit (c′) is preferably 10% to 100% bymole, more preferably 20% to 100% by mole, still more preferably 30% to100% by mole, and most preferably 40% to 100% by mole, with respect toall the repeating units in the resin (C).

The content of the repeating unit (c*) is preferably 5% to 70% by mole,more preferably 5% to 60% by mole, still more preferably 10% to 50% bymole, and most preferably 10% to 40% by mole, with respect to all therepeating units in the resin (C). The content of the repeating unithaving a fluorine atom, which is used together with the repeating unit(c*), is preferably 10% to 95% by mole, more preferably 15% to 85% bymole, still more preferably 20% to 80% by mole, and most preferably 25%to 75% by mole, with respect to all the repeating units in the resin(C).

The content of the repeating unit (c″) is preferably 10% to 100% bymole, more preferably 20% to 100% by mole, still more preferably 30% to100% by mole, and most preferably 40% to 100% by mole, with respect toall the repeating units (c″) in the resin (C).

The fluorine atom in the resin (C) may be contained in the main chain ofthe resin or may be substituted in a side chain of the resin.

The resin (C) may further have another repeating unit. Preferred aspectsof the other repeating units include the following ones.

(cy1) A repeating unit which has a fluorine atom, and is stable to anacid, and sparingly soluble or insoluble in an alkali developer.

(cy2) A repeating unit which has no fluorine atom, and is stable to anacid, and sparingly soluble or insoluble in an alkali developer.

(cy3) A repeating unit which has a fluorine atom and a polar group otherthan (x) and (z) described above.

(cy4) A repeating unit which has no fluorine atom and has a polar groupother than (x) and (z) described above.

In the repeating units of (cy1) and (cy2), “being sparingly soluble orinsoluble in an alkali developer” means that (cy1) and (cy2) do notinclude an alkali-soluble group or a group that produces analkali-soluble group by the action of an acid or an alkali developer(for example, an acid-decomposable group or a polarity conversiongroup).

The repeating units (cy1) and (cy2) preferably have an alicyclichydrocarbon structure having no polar group.

Preferred aspects of the repeating units (cy1) to (cy4) are shown below.

The repeating units (cy1) and (cy2) are each preferably a repeating unitrepresented by General Formula (CIII).

In General Formula (CIII),

R_(c31) represents a hydrogen atom, an alkyl group which may besubstituted with a fluorine atom, a cyano group, or a —CH₂—O—Rac₂ group.In the formula, Rac₂ represents a hydrogen atom, an alkyl group, or anacyl group. R_(c31) is preferably a hydrogen atom, a methyl group, ahydroxymethyl group, or a trifluoromethyl group, and particularlypreferably the hydrogen atom or the methyl group.

R_(c32) represents a group having an alkyl group, a cycloalkyl group, analkenyl group, a cycloalkenyl group, or an aryl group. These groups maybe substituted with a group including a silicon atom, a fluorine atom,or the like.

L_(c3) represents a single bond or a divalent linking group.

In General Formula (CIII), the alkyl group of R_(c32) is preferably alinear or branched alkyl group having 3 to 20 carbon atoms.

The cycloalkyl group is preferably a cycloalkyl group having 3 to 20carbon atoms.

The alkenyl group is preferably an alkenyl group having 3 to 20 carbonatoms.

The cycloalkenyl group is preferably a cycloalkenyl group having 3 to 20carbon atoms.

The aryl group is preferably a phenyl group having 6 to 20 carbon atomsor a naphthyl group, and these may have a substituent.

R_(c32) is preferably an unsubstituted alkyl group or an alkyl groupsubstituted with a fluorine atom. The divalent linking group of L_(c3)is preferably an alkylene group (preferably having 1 to 5 carbon atoms),an oxy group, a phenylene group, or an ester bond (a group representedby —COO—).

The repeating units (cy1) and (cy2) are each preferably a repeating unitrepresented by General Formula (C4) or (C5).

In General Formulae (C4) and (C5),

R_(c5) represents a hydrocarbon group which has at least one cyclicstructure and has neither a hydroxyl group nor a cyano group.

Rac represents a hydrogen atom, an alkyl group which may be substitutedwith a fluorine atom, a cyano group, or a —CH₂—O—Race group. In theformula, Race represents a hydrogen atom, an alkyl group, or an acylgroup. Rac is preferably the hydrogen atom, a methyl group, ahydroxymethyl group, or a trifluoromethyl group, and particularlypreferably the hydrogen atom or the methyl group.

The cyclic structure contained in R_(c5) includes a monocyclichydrocarbon group and a polycyclic hydrocarbon group. Examples of themonocyclic hydrocarbon group include a cycloalkyl group having 3 to 12carbon atoms and a cycloalkenyl group having 3 to 12 carbon atoms. Apreferred monocyclic hydrocarbon group is a monocyclic hydrocarbon grouphaving 3 to 7 carbon atoms.

Examples of the polycyclic hydrocarbon group include a ring-assembledhydrocarbon group and a crosslinked cyclic hydrocarbon group. Examplesof the crosslinked cyclic hydrocarbon ring include a bicyclichydrocarbon ring, a tricyclic hydrocarbon ring, and a tetracyclichydrocarbon ring. Further, other examples of the crosslinked cyclichydrocarbon ring include a fused cyclic hydrocarbon ring (for example, afused ring formed by fusing a plurality of 5- to 8-membered cycloalkanerings). Preferred examples of the crosslinked cyclic hydrocarbon ringinclude a norbornyl group and an adamantyl group.

These alicyclic hydrocarbon groups may have a substituent, and preferredexamples of the substituent include a halogen atom, an alkyl group, ahydroxyl group protected with a protective group, and an amino groupprotected with a protective group. Preferred examples of the halogenatom include bromine, chlorine, and fluorine atoms, and preferredexamples of the alkyl group include methyl, ethyl, butyl, and t-butylgroups. The alkyl group may further have a substituent, and examples ofthe substituent which may further be contained include a halogen atom,an alkyl group, a hydroxyl group protected with a protective group, andan amino protected with a protective group.

Examples of the protective group include an alkyl group, a cycloalkylgroup, an aralkyl group, a substituted methyl group, a substituted ethylgroup, an alkoxycarbonyl group, and an aralkyloxycarbonyl group.Preferred examples of the alkyl group include an alkyl group having 1 to4 carbon atoms; preferred examples of the substituted methyl groupinclude methoxymethyl, methoxythiomethyl, benzyloxymethyl,t-butoxymethyl, and 2-methoxyethoxymethyl groups; preferred examples ofthe substituted ethyl group include 1-ethoxyethyl and1-methyl-1-methoxyethyl; preferred examples of the acyl group include analiphatic acyl group having 1 to 6 carbon atoms, such as formyl, acetyl,propionyl, butyryl, isobutyryl, valeryl, and pivaloyl groups; andexamples of the alkoxycarbonyl group include an alkoxycarbonyl grouphaving 2 to 4 carbon atoms.

R_(c6) represents an alkyl group, a cycloalkyl group, an alkenyl group,a cycloalkenyl group, an alkoxycarbonyl group, or an alkylcarbonyloxygroup. These groups may be substituted with a fluorine atom or a siliconatom.

The alkyl group of R_(c6) is preferably a linear or branched alkyl grouphaving 1 to 20 carbon atoms. The cycloalkyl group is preferably acycloalkyl group having 3 to 20 carbon atoms.

The alkenyl group is preferably an alkenyl group having 3 to 20 carbonatoms.

The cycloalkenyl group is preferably a cycloalkenyl group having 3 to 20carbon atoms.

The alkoxycarbonyl group is preferably an alkoxycarbonyl group having 2to 20 carbon atoms.

The alkylcarbonyloxy group is preferably an alkylcarbonyloxy grouphaving 2 to 20 carbon atoms.

n represents an integer of 0 to 5. In a case where n is 2 or more, aplurality of R_(c6) 's may be the same as or different from each other.

R_(c6) is preferably an unsubstituted alkyl group or an alkyl groupsubstituted with a fluorine atom, and particularly preferably atrifluoromethyl group or a t-butyl group.

It is also preferable that (cy1) and (cy2) are each a repeating unitrepresented by General Formula (CII-AB).

In Formula (CII-AB),

R_(c11)′ and R_(c12)′ each independently represent a hydrogen atom, acyano group, a halogen atom, or an alkyl group.

Zc′ represents an atomic group for forming an alicyclic structure, whichincludes two bonded carbon atoms (C—C).

Furthermore, General Formula (CII-AB) is more preferably General Formula(CII-AB1) or General Formula (CII-AB2).

In Formulae (CII-AB1) and (CII-AB2),

Rc₁₃′ to Rc₁₆′ each independently represent a hydrogen atom, a halogenatom, an alkyl group, or a cycloalkyl group.

Further, at least two of Rc₁₃′, . . . , or Rc₁₆′ may be bonded to eachother to form a ring.

n represents 0 or 1.

Specific examples of (cy1) and (cy2) are shown below, but the presentinvention is not limited thereto. In the formulae, Ra represents H, CH₃,CH₂OH, CF₃, or CN.

Each of (cy3) and (cy4) is preferably a repeating unit having a hydroxylgroup or a cyano group as a polar group. This improves the affinity forthe developer. The repeating unit having a hydroxyl group or a cyanogroup is preferably a repeating unit having an alicyclic hydrocarbonstructure substituted with a hydroxyl group or a cyano group. In thealicyclic hydrocarbon structure substituted with a hydroxyl group or acyano group, the alicyclic hydrocarbon structure is preferably anadamantyl group, a diadamantyl group, or a norbornyl group. Preferredexamples of the alicyclic hydrocarbon structure substituted with ahydroxyl group or a cyano group include a monohydroxyadamantyl group, adihydroxyadamantyl group, a monohydroxydiadamantyl group, adihydroxydiadamantyl group, and a norbornyl group substituted with acyano group.

Examples of the repeating unit having the atomic group include repeatingunits represented by General Formulae (CAIIa) to (CAIId).

In General Formulae (CAIIa) to (CAIId),

R₁c represents a hydrogen atom, a methyl group, a trifluoromethyl group,or a hydroxymethyl group.

R₂c to R₁c each independently represent a hydrogen atom, a hydroxylgroup, or a cyano group. It should be noted that at least one of R₂c, .. . , or R₄c represents a hydroxyl group or a cyano group. Preferably,one or two of R₂c to R₄c are hydroxyl groups, and the remaining is ahydrogen atom. In General Formula (CAIIa), it is more preferable thattwo of R₂c to R₄c are hydroxyl groups and the remaining is a hydrogenatom.

Specific examples of the repeating units represented by (cy3) and (cy4)are shown below, but the present invention is not limited thereto.

The content of the repeating units represented by (cy1) to (cy4) ispreferably 5% to 40% by mole, more preferably 5% to 30% by mole, andstill more preferably 10% to 25% by mole, with respect to all therepeating units in the resin (C).

The resin (C) may have a plurality of repeating units represented by(cy1) to (cy4).

The content of fluorine atoms in the resin (C) is preferably 5% to 80%by mass, and more preferably 10% to 80% by mass, with respect to themolecular weight of the resin (C). Further, the repeating unitcontaining a fluorine atom is preferably 10% to 100% by mass, and morepreferably 30% to 100% by mass, with respect to all the repeating unitsin the resin (C).

From the viewpoint of improving the uneven distribution, the molecularweight of the fluorine-containing compound (C) is preferably 1,000 to100,000.

The weight-average molecular weight of the resin (C) is preferably 1,000to 100,000, more preferably 1,000 to 50,000, and still more preferably2,000 to 15,000.

The molecular weight distribution (Mw/Mn, also referred to as adispersity) of the resin (C) is preferably in the range of 1 to 3, morepreferably 1 to 2, still more preferably 1 to 1.8, and most preferablyin the range of 1 to 1.5.

As the resin (C), various commercially available products can be used,and in the same manner as the resin (A), the resin (C) can besynthesized according to an ordinary method (for example, radicalpolymerization).

The fluorine-containing compound (C) can be used singly or incombination of two or more kinds thereof.

From the viewpoint of resolution, the content of the fluorine-containingcompound (C) in the composition of the embodiment of the presentinvention is preferably 0.01% to 10% by mass, more preferably 0.1% to10% by mass, and still more preferably 0.1% to 5% by mass, with respectto the total solid content of the composition of the embodiment of thepresent invention.

[Acid Diffusion Control Agent]

The composition of the embodiment of the present invention preferablycontains an acid diffusion control agent. The acid diffusion controlagent acts as a quencher that suppresses a reaction of theacid-decomposable resin in the unexposed area by excessive generatedacids by trapping the acids generated from a photoacid generator and thelike upon exposure.

For example, a basic compound (DA), a basic compound (DB) havingbasicity reduced or lost upon irradiation with actinic rays orradiation, an onium salt (DC) which is a weak acid relative to an acidgenerator, a low-molecular-weight compound (DD) having a nitrogen atomand a group that leaves by the action of an acid, an onium salt compound(DE) having a nitrogen atom in the cationic moiety, can be used as theacid diffusion control agent. In the composition of the embodiment ofthe present invention, a known acid diffusion control agent can beappropriately used. For example, the known compounds disclosed inparagraphs [0627] to [0664] of the specification of US2016/0070167A1,paragraphs [0095] to [0187] of the specification of US2015/0004544A1,paragraphs [0403] to [0423] of the specification of US2016/0237190A1,and paragraphs [0259] to [0328] of the specification of US2016/0274458A1can be suitably used as the acid diffusion control agent.

As the basic compound (DA), compounds having structures represented byGeneral Formulae (A) to (E) are preferable.

In General Formulae (A) and (E),

R²⁰⁰, R²⁰¹, and R²⁰² may be the same as or different from each other,and each independently represent a hydrogen atom, an alkyl group(preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferablyhaving 3 to 20 carbon atoms), or an aryl group (having 6 to 20 carbonatoms). R²⁰¹ and R²⁰² may be bonded to each other to form a ring.

R²⁰³, R²⁰⁴, R²⁰⁵, and R²⁰⁶ may be the same as or different from eachother and each independently represent an alkyl group having 1 to 20carbon atoms.

The alkyl group in each of General Formulae (A) and (E) may have asubstituent or may be unsubstituted.

With regard to the alkyl group, the alkyl group having a substituent ispreferably an aminoalkyl group having 1 to 20 carbon atoms, ahydroxyalkyl group having 1 to 20 carbon atoms, or a cyanoalkyl grouphaving 1 to 20 carbon atoms.

The alkyl groups in each of General Formulae (A) and (E) are morepreferably unsubstituted.

As the basic compound (DA), thiazole, benzothiazole, oxazole,benzoxazole, guanidine, aminopyrrolidine, pyrazole, pyrazoline,piperazine, aminomorpholine, aminoalkylmorpholine, piperidine, orcompounds having these structures are preferable; and a compound havinga thiazole structure, a benzothiazole structure, an oxazole structure, abenzoxazole structure, an imidazole structure, a diazabicyclo structure,an onium hydroxide structure, an onium carboxylate structure, atrialkylamine structure, an aniline structure, or a pyridine structure,an alkylamine derivative having a hydroxyl group and/or an ether bond,and an aniline derivative having a hydroxyl group and/or an ether bond,or the like is more preferable.

The basic compound (DB) having basicity reduced or lost upon irradiationwith actinic rays or radiation (hereinafter also referred to as a“compound (DB)”) is a compound which has a proton-accepting functionalgroup, and decomposes under irradiation with actinic rays or radiationto exhibit deterioration in proton-accepting properties, noproton-accepting properties, or a change from the proton-acceptingproperties to acidic properties.

The proton-accepting functional group refers to a functional grouphaving a group or an electron which is capable of electrostaticallyinteracting with a proton, and for example, means a functional groupwith a macrocyclic structure, such as a cyclic polyether, or afunctional group having a nitrogen atom having an unshared electron pairnot contributing to n-conjugation. The nitrogen atom having an unsharedelectron pair not contributing to it-conjugation is, for example, anitrogen atom having a partial structure represented by the followingformula.

Preferred examples of the partial structure of the proton-acceptingfunctional group include a crown ether structure, an azacrown etherstructure, primary to tertiary amine structures, a pyridine structure,an imidazole structure, and a pyrazine structure.

The compound (DB) decomposes upon irradiation with actinic rays orradiation to generate a compound exhibiting deterioration inproton-accepting properties, no proton-accepting properties, or a changefrom the proton-accepting properties to acidic properties. Here,exhibiting deterioration in proton-accepting properties, noproton-accepting properties, or a change from the proton-acceptingproperties to acidic properties means a change of proton-acceptingproperties due to the proton being added to the proton-acceptingfunctional group, and specifically a decrease in the equilibriumconstant at chemical equilibrium in a case where a proton adduct isgenerated from the compound (DB) having the proton-accepting functionalgroup and the proton.

The proton-accepting properties can be confirmed by performing pHmeasurement.

The acid dissociation constant pKa of the compound generated bydecomposition of the compound (DB) upon irradiation with actinic rays orradiation preferably satisfies pKa<−1, and is more preferably satisfies−13<pKa<−1, and still more preferably 13<pKa<−3.

The acid dissociation constant pKa refers to an acid dissociationconstant pKa in an aqueous solution, and is defined, for example, inChemical Handbook (II) (Revised 4th Edition, 1993, compiled by theChemical Society of Japan, Maruzen Company, Ltd.). A lower value of theacid dissociation constant pKa indicates higher acid strength.Specifically, the acid dissociation constant pKa in an aqueous solutioncan be actually measured by using an infinite-dilution aqueous solutionand measuring the acid dissociation constant at 25° C. Alternatively,the acid dissociation constant pKa can also be determined using thefollowing software package 1 by computation from a value with respect toa Hammett substituent constant and the database of publicly knownliterature values. Any of the values of pKa described in the presentspecification indicate values determined by computation using thesoftware package.

Software Package 1: Advanced Chemistry Development (ACD/Labs) Software V8.14 for Solaris (1994-2007 ACD/Labs).

In the composition of the embodiment of the present invention, the oniumsalt (DC) which is a weak acid relative to a photoacid generator can beused as the acid diffusion control agent.

In a case where the photoacid generator and the onium salt thatgenerates an acid which is a weak acid relative to an acid generatedfrom the photoacid generator are mixed and used, an acid generated fromthe photoacid generator upon irradiation with actinic rays or radiationproduces an onium salt having a strong acid anion by discharging theweak acid through salt exchange in a case where the acid collides withan onium salt having an unreacted weak acid anion. In this process, thestrong acid is exchanged with a weak acid having a lower catalyticability, and thus, the acid is apparently deactivated and the aciddiffusion can be controlled.

As the onium salt which is a weak acid relative to the photoacidgenerator, compounds represented by General Formulae (d1-1) to (d1-3)are preferable.

In the formula, R⁵¹ is a hydrocarbon group which may have a substituent,Z^(2c) is a hydrocarbon group having 1 to 30 carbon atoms, which mayhave a substituent (provided that carbon adjacent to S is notsubstituted with a fluorine atom), R⁵² is an organic group, Y³ is alinear, branched, or cyclic alkylene group or an arylene group, Rf is ahydrocarbon group including a fluorine atom, and M⁺'s are eachindependently an ammonium cation, a sulfonium cation, or an iodoniumcation.

Preferred examples of the sulfonium cation or iodonium cationrepresented by M⁺ include the sulfonium cation exemplified for GeneralFormula (ZI) and the iodonium cation exemplified for General Formula(ZII).

The onium salt (DC) which is a weak acid relative to a photoacidgenerator may be a compound having a cationic moiety and an anionicmoiety in the same molecule, in which the cationic moiety and theanionic moiety are linked by a covalent bond (hereinafter also referredto as a “compound (DCA)”).

The compound (DCA) is preferably a compound represented by any ofGeneral Formulae (C-1) to (C-3).

In General Formulae (C-1) to (C-3),

R₁, R₂, and R₃ each independently represent a substituent having 1 ormore carbon atoms.

L₁ represents a divalent linking group that links a cationic moiety withan anionic moiety, or a single bond.

—X⁻ represents an anionic moiety selected from —COO⁻, —SO₃ ⁻, —SO₂ ⁻,and —N⁻—R₄. R₄ represents a monovalent substituent having at least oneof a carbonyl group: —C(═O)—, a sulfonyl group: —S(═O)₂—, or a sulfinylgroup: —S(═O)— at a site for linking to an adjacent N atom.

R₁, R₂, R₃, R₄, and L₁ may be bonded to each other to form a ringstructure. Further, in General Formula (C-3), two of R₁ to R₃ togetherrepresent one divalent substituent, and may be bonded to an N atom by adouble bond.

Examples of the substituent having 1 or more carbon atoms in each of R₁to R₃ include an alkyl group, a cycloalkyl group, an aryl group, analkyloxycarbonyl group, a cycloalkyloxycarbonyl group, anaryloxycarbonyl group, an alkylaminocarbonyl group, acycloalkylaminocarbonyl group, and an arylaminocarbonyl group. The alkylgroup, the cycloalkyl group, or the aryl group is preferable.

Examples of L₁ as a divalent linking group include a linear or branchedalkylene group, a cycloalkylene group, an arylene group, a carbonylgroup, an ether bond, an ester bond, an amide bond, a urethane bond, aurea bond, and a group formed by a combination of two or more of thesegroups. L₁ is preferably the alkylene group, the arylene group, theether bond, the ester bond, and the group formed by a combination of twoor more of these groups.

The low-molecular-weight compound (DD) having a nitrogen atom and havinga group that leaves by the action of an acid (hereinafter also referredto as a “compound (DD)”) is preferably an amine derivative having agroup that leaves by the action of an acid on the nitrogen atom.

As the group that leaves by the action of an acid, an acetal group, acarbonate group, a carbamate group, a tertiary ester group, a tertiaryhydroxyl group, or a hemiaminal ether group is preferable, and thecarbamate group or the hemiaminal ether group is more preferable.

The molecular weight of the compound (DD) is preferably 100 to 1,000,more preferably 100 to 700, and still more preferably 100 to 500.

The compound (DD) may have a carbamate group having a protective groupon the nitrogen atom. The protective group constituting the carbamategroup is represented by General Formula (d-1).

In General Formula (d-1),

R_(b)'s each independently represent a hydrogen atom, an alkyl group(preferably having 1 to 10 carbon atoms), a cycloalkyl group (preferablyhaving 3 to 30 carbon atoms), an aryl group (preferably having 3 to 30carbon atoms), an aralkyl group (preferably having 1 to 10 carbonatoms), or an alkoxyalkyl group (preferably having 1 to 10 carbonatoms). R_(b)'s may be bonded to each other to form a ring.

The alkyl group, the cycloalkyl group, the aryl group, or the aralkylgroup represented by R_(b) may be each independently substituted with afunctional group such as a hydroxyl group, a cyano group, an aminogroup, a pyrrolidino group, a piperidino group, a morpholino group, andan oxo group, an alkoxy group, or a halogen atom. The same applies tothe alkoxyalkyl group represented by R_(b).

As R_(b), a linear or branched alkyl group, a cycloalkyl group, or anaryl group is preferable, and the linear or branched alkyl group, or thecycloalkyl group is more preferable.

Examples of the ring formed by the mutual linkage of two of R_(b)'sinclude an alicyclic hydrocarbon, an aromatic hydrocarbon, aheterocyclic hydrocarbon, and derivatives thereof.

Examples of the specific structure of the group represented by GeneralFormula (d-1) include, but are not limited to, the structures disclosedin paragraph [0466] of the specification of US2012/0135348A1.

The compound (DD) preferably has a structure represented by GeneralFormula (6).

In General Formula (6),

1 represents an integer of 0 to 2, m represents an integer of 1 to 3,and these satisfy 1+m=3.

R_(a) represents a hydrogen atom, an alkyl group, a cycloalkyl group, anaryl group, or an aralkyl group. In a case where 1 is 2, two of R_(a)'smay be the same as or different from each other, and the two of R_(a)'smay be linked to each other to form a heterocycle with the nitrogen atomin the formula. This heterocycle may include a heteroatom other than thenitrogen atom in the formula.

R_(b) has the same definition as R_(b) in General Formula (d-1), andpreferred examples are also the same.

In General Formula (6), the alkyl group, the cycloalkyl group, the arylgroup, and the aralkyl group as R_(a) may be each independentlysubstituted with the same groups as the group mentioned above as a groupwhich may be substituted in the alkyl group, the cycloalkyl group, thearyl group, and the aralkyl group as R_(b).

Specific examples of the alkyl group, the cycloalkyl group, the arylgroup, and the aralkyl group (these groups may be substituted with thegroups as described above) of R_(a) include the same groups as thespecific examples as described above with respect to R_(b).

Specific examples of the particularly preferred compound (DD) in thepresent invention include, but are not limited to, the compoundsdisclosed in paragraph [0475] of the specification of US2012/0135348A1.

The onium salt compound (DE) having a nitrogen atom in the cationicmoiety (hereinafter also referred to as a “compound (DE)”) is preferablya compound having a basic moiety including a nitrogen atom in thecationic moiety. The basic moiety is preferably an amino group, and morepreferably an aliphatic amino group. All of the atoms adjacent to thenitrogen atom in the basic moiety are still more preferably hydrogenatoms or carbon atoms. In addition, from the viewpoint of improvingbasicity, it is preferable that an electron-withdrawing functional group(such as a carbonyl group, a sulfonyl group, a cyano group, and ahalogen atom) is not directly linked to the nitrogen atom.

Preferred specific examples of the compound (DE) include, but are notlimited to, the compounds disclosed in paragraph [0203] ofUS2015/0309408A1.

In the present invention, the acid diffusion control agent is preferablya basic compound (DA), and among those, a compound having a structurerepresented by General Formula (C) is more preferable, and a compoundrepresented by General Formula (DAC1), (DAC2), or (DAC3) is morepreferable.

In General Formulae (DAC1), (DAC2), and (DAC3), Ar^(D1) to Ar^(D3) eachindependently represent an aromatic group.

Ar^(D1) to Ar^(D3) preferably represent an aryl group, and morepreferably a phenyl group. The aromatic group represented by each ofAr^(D1) to Ar^(D3) may have a substituent, examples of the substituentinclude an alkyl group, an alkoxy group, and an ester group, and amethoxy group is particularly preferable.

Preferred examples of the acid diffusion control agent are shown below.

In the composition of the embodiment of the present invention, the aciddiffusion control agents may be used singly or in combination of two ormore kinds thereof.

The content of the acid diffusion control agent (in a case where aplurality of kinds of the acid diffusion control agents are present, atotal content thereof) in the composition of the embodiment of thepresent invention is preferably 0.001% to 20% by mass, and morepreferably 0.01% to 10% by mass, with respect to the total solid contentof the composition.

[Compound Having Lactone Structure or Sultone Structure]

The composition of the embodiment of the present invention preferablyincludes a compound having a lactone structure or a sultone structure.

Examples of the compound having a lactone structure or a sultonestructure include a resin having a lactone group or a sultone group anda photoacid generator having a lactone group or a sultone group, each inthe resin (A).

[Surfactant]

The composition of the embodiment of the present invention may furtherinclude a surfactant. By containing the surfactant, in a case where anexposure light source at a wavelength of 250 nm or less, in particular,220 nm or less is used, it is possible to form a pattern with goodsensitivity and resolution and excellent adhesiveness and lessdevelopment defects.

It is particularly preferable to use a fluorine-based and/orsilicon-based surfactant as the surfactant.

Examples of the fluorine-based and/or silicon-based surfactants includethe surfactants described in [0276] of the specification ofUS2008/0248425A. In addition, EFTOP EF301 or EF303 (manufactured byShin-Akita Chemical Co., Ltd.); FLORAD FC430, 431, or 4430 (manufacturedby Sumitomo 3M Inc.); MEGAFACE F171, F173, F176, F189, F113, F110, F177,F120, or R08 (manufactured by DIC Corporation); SURFLON S-382, SC101,102, 103, 104, 105, or 106 (manufactured by Asahi Glass Co., Ltd.);TROYSOL S-366 (manufactured by Troy Chemical Corporation); GF-300 orGF-150 (manufactured by Toagosei Chemical Industry Co., Ltd.); SURFLONS-393 (manufactured by Seimi Chemical Co., Ltd.); EFTOP EF121, EF122A,EF122B, RF122C, EF125M, EF135M, EF351, EF352, EF801, EF802, or EF601(manufactured by JEMCO Inc.); PF636, PF656, PF6320, or PF6520(manufactured by OMNOVA Solutions Inc.); or FTX-204G, 208G, 218G, 230G,204D, 208D, 212D, 218D, or 222D (manufactured by NEOS COMPANY LIMITED)may be used. In addition, a polysiloxane polymer, KP-341 (manufacturedby Shin-Etsu Chemical Co., Ltd.), can also be used as the silicon-basedsurfactant.

Furthermore, the surfactant may be synthesized using a fluoroaliphaticcompound produced by a telomerization method (also referred to as atelomer method) or an oligomerization method (also referred to as anoligomer method), in addition to the known surfactants as shown above.Specifically, a polymer comprising a fluoroaliphatic group derived fromthe fluoroaliphatic compound may also be used as the surfactant. Thefluoroaliphatic compound can be synthesized in accordance with themethod described in JP2002-090991A.

In addition, another surfactant other than the fluorine-based and/orsilicon-based surfactants, described in [0280] of US2008/0248425A, mayalso be used.

These surfactants may be used singly or in combination of two or morekinds thereof.

In a case where the composition of the embodiment of the presentinvention includes a surfactant, a content thereof is preferably0.00001% to 2% by mass, more preferably 0.0001% to 2% by mass, and morepreferably 0.0005% to 1% by mass, with respect to the total solidcontent of the composition.

[Other Additives]

The composition of the embodiment of the present invention can contain,in addition to the components described above, a carboxylic acid, anonium carboxylate salt, a dissolution inhibiting compound having amolecular weight of 3,000 or less described in Proceeding of SPIE,2724,355 (1996) and the like, a dye, a plasticizer, a photosensitizer, alight absorber, an antioxidant, and the like as appropriate.

In particular, carboxylic acid can be preferably used for improving theperformance. The carboxylic acid is preferably an aromatic carboxylicacid such as benzoic acid or naphthoic acid.

In a case where the composition of the embodiment of the presentinvention includes a carboxylic acid, the content of the carboxylic acidis preferably 0.01% to 10% by mass, more preferably 0.01% to 5% by mass,and still more preferably 0.01% to 3% by mass, with respect to the totalsolid content of the composition.

The actinic ray-sensitive or radiation-sensitive resin composition ofthe embodiment of the present invention is preferably used with a filmthickness of 10 to 250 nm, more preferably 20 to 200 nm, and still morepreferably 30 to 100 nm, from the viewpoint of improving resolvingpower. Such a film thickness can be obtained by setting theconcentration of solid contents in the composition to an appropriaterange to provide the composition with a suitable viscosity and improvethe coating property and the film forming property.

The concentration of solid contents of the actinic ray-sensitive orradiation-sensitive resin composition in the embodiment of the presentinvention is usually 1.0% to 10% by mass, preferably 2.0% to 5.7% bymass, and more preferably 2.0% to 5.3% by mass. By setting theconcentration of solid contents within the range, the resist solutioncan be uniformly applied onto a substrate, and further, it is possibleto form a resist pattern having excellent line width roughness.

The concentration of solid contents is a mass percentage of the mass ofother components excluding the solvent with respect to the total mass ofthe actinic ray-sensitive or radiation-sensitive resin composition.

[Use]

The composition of the embodiment of the present invention relates to anactinic ray-sensitive or radiation-sensitive resin composition havingproperties changed by undergoing a reaction upon irradiation withactinic rays or radiation. More specifically, the composition of theembodiment of the present invention relates to an actinic ray-sensitiveor radiation-sensitive resin composition which is used in a step ofmanufacturing a semiconductor such as an integrated circuit (IC), forthe manufacture of a circuit board for a liquid crystal, a thermal head,or the like, the manufacture of a mold structure for imprinting, otherphotofabrication steps, or production of a planographic printing plateor an acid-curable composition. A pattern formed in the presentinvention can be used in an etching step, an ion implantation step, abump electrode forming step, a rewiring forming step, amicroelectromechanical system (MEMS), or the like.

In addition, the present invention also relates to an actinicray-sensitive or radiation-sensitive resin composition for manufacturinga photo mask.

[Actinic Ray-Sensitive or Radiation-Sensitive Film]

The present invention also relates to an actinic ray-sensitive orradiation-sensitive film (preferably a resist film) formed with theactinic ray-sensitive or radiation-sensitive resin composition of theembodiment of the present invention. Such a film is formed, for example,by applying the composition of the embodiment of the present inventiononto a support such as a substrate. The thickness of this film ispreferably 0.02 to 0.1 μm. As a method for applying the composition onthe substrate, a suitable application method such as spin coating, rollcoating, flow coating, dip coating, spray coating, and doctor coating isapplied on a substrate, but the spin coating is preferable and therotation speed is preferably 1,000 to 3,000 rotations per minute (rpm).The coating film is prebaked at 60° C. to 150° C. for 1 to 20 minutes,and preferably at 80° C. to 120° C. for 1 to 10 minutes to form a thinfilm.

For a material constituting a substrate to be processed and an outermostlayer thereof, for example, in a case of a semiconductor wafer, asilicon wafer can be used, and examples of the material forming theoutermost layer include Si, SiO₂, SiN, SiON, and TiN, WSi, BPSG, SOG,and an organic antireflection film.

Before forming the resist film, an antireflection film may be previouslycoated on the substrate.

As the antireflection film, any of an inorganic film type antireflectionfilm such as titanium, titanium dioxide, titanium nitride, chromiumoxide, carbon, and amorphous silicon, and an organic film typeantireflection film formed of a light absorber and a polymer materialcan be used. Further, as the organic antireflection film, a commerciallyavailable organic antireflection film such as DUV30 series or DUV-40series manufactured by Brewer Science Inc., or AR-2, AR-3, or AR-5manufactured by Shipley Co., Ltd. can be used.

Moreover, in the pattern forming method of the embodiment of the presentinvention, a topcoat may be formed on the upper layer of the resistfilm. It is preferable that the topcoat is not mixed with the resistfilm and can be uniformly applied to the upper layer of the resist film.

The topcoat is not particularly limited, a topcoat known in the relatedart can be formed by a method known in the related art, and for example,the topcoat can be formed in accordance with the description inparagraphs 0072 to 0082 of JP2014-059543A.

For example, it is preferable that a topcoat containing a basic compoundas described in JP2013-061648A is formed on a resist film. Specificexamples of the basic compound which can be included in the topcoatinclude the same ones as those for the above-mentioned acid diffusioncontrol agent.

In addition, the topcoat preferably includes a compound which includesat least one group or bond selected from the group consisting of anether bond, a thioether bond, a hydroxyl group, a thiol group, acarbonyl bond, and an ester bond.

Furthermore, the topcoat preferably contains a resin. The resin whichcan be contained in the topcoat is not particularly limited, but thesame resin as the hydrophobic resin which can be included in the actinicray-sensitive or radiation-sensitive composition can be used.

With regard to the hydrophobic resin, reference can be made to thedescriptions in [0017] to [0023] of JP2013-061647A ([0017] to [0023] ofthe corresponding US2013/0244438A), and [0016] to [0165] ofJP2014-056194A, the contents of which are incorporated herein byreference.

The topcoat preferably includes a resin containing a repeating unithaving an aromatic ring. By containing the repeating unit having anaromatic ring, a secondary electron-generating efficiency and anacid-generating efficiency from a compound that generates an acid withactinic rays or radiation increase, particularly upon irradiation withelectron beams or EUV exposure, and thus, an effect of realizing highsensitivity and high resolution in the formation of a pattern can beexpected.

In a case where the topcoat includes a plurality of resins, it ispreferable that the topcoat includes at least one resin (XA) having afluorine atom and/or a silicon atom. It is more preferable that thetopcoat composition includes at least one resin (XA) having a fluorineatom and/or a silicon atom, and a resin (XB) having a content of afluorine atom and/or silicon atom which is smaller than that of theresin (XA). As a result, in a case where a topcoat film is formed, theresin (XA) is unevenly distributed on a surface of the topcoat film, andthus, that it is possible to improve performance such as developmentcharacteristics and immersion liquid followability.

In addition, the topcoat may contain an acid generator and acrosslinking agent.

The topcoat is typically formed from a composition for forming atopcoat.

For the composition for forming a topcoat, it is preferable that therespective components are dissolved in a solvent and filtered using afilter. The filter is preferably made of polytetrafluoroethylene,polyethylene, or nylon, which has a pore size of 0.1 μm or less, morepreferably 0.05 μm or less, and still more preferably 0.03 μm or less.Further, in a case where the concentration of solid contents of thecomposition is high (for example, 25% by mass or more), the pore size ofa filter used for filtration using a filter is preferably 3 μm or less,more preferably 0.5 μm or less, still more preferably 0.3 μm or less.The filter is preferably a polytetrafluoroethylene-made,polyethylene-made, or nylon-made filter. In the filtration using afilter as shown in the specification of JP2002-062667A, circulatingfiltration may be performed or the filtration may be performed by thelinkage of a plurality of kinds of filters in series or in parallel. Inaddition, the composition may be filtered in plural times. Furthermore,the composition may be subjected to a deaeration treatment or the likebefore or after filtration using a filter.

The composition for forming a topcoat preferably does not includeimpurities such as a metal. The content of the metal components includedin these materials is preferably 10 ppm or less, more preferably 5 ppmor less, and still more preferably 1 ppm or less, and it is particularlypreferable that substantially no metal component is included (below adetection limit of the measuring apparatus).

It is also preferable to partially or wholly subjecting the inside of adevice used in a producing process (a process for synthesizing a rawmaterial, and the like) of a raw material (a resin, a photoacidgenerator, and the like) of a resist composition to a glass liningtreatment so that a content of metal impurities of the resistcomposition is adjusted to be small (for example, on the order of ppm bymass). Such a method is described, for example, in The Chemical Daily,Dec. 21, 2017.

In a case where the exposure which will be described later is liquidimmersion exposure, the topcoat is arranged between the resist film andthe immersion liquid, and also functions as a layer which does not bringthe resist film into direct contact with the immersion liquid. In thiscase, preferred characteristics required for the topcoat (compositionfor forming a topcoat) are coating suitability onto the resist film,transparency to radiation, particularly to light at 193 nm, and sparingsolubility in an immersion liquid (preferably water). Further, it ispreferable that the topcoat is not mixed with the resist film and can beuniformly applied to a surface of the resist film.

Moreover, in order to uniformly apply the composition for forming atopcoat onto a surface of the resist film while not dissolving theresist film, it is preferable that the composition for forming a topcoatcontains a solvent in which the resist film is not dissolved. It is morepreferable to use a solvent of a component different from a developer(organic developer) containing an organic solvent which will bedescribed in detail later as the solvent in which the resist film is notdissolved.

A method for applying the composition for forming a topcoat is notparticularly limited, and a spin coating method, a spray coating method,a roller coating method, a dip method, or the like which is known in therelated art can be used.

The thickness of the topcoat is not particularly limited, but is usually5 nm to 300 nm, preferably 10 nm to 300 nm, more preferably 20 nm to 200nm, and still more preferably 30 nm to 100 nm, from the viewpoint oftransparency to an exposure light source.

After forming the topcoat, the substrate is post-baked (PB) asnecessary.

From the viewpoint of resolution, it is preferable that the refractiveindex of the topcoat is close to that of the resist film.

The topcoat is preferably insoluble in an immersion liquid, and morepreferably insoluble in water. With regard to the receding contact angleof the topcoat, the receding contact angle (23° C.) of the immersionliquid with respect to the topcoat is preferably 50 to 100 degrees, andmore preferably 80 to 100 degrees, from the viewpoint of immersionliquid tracking properties.

In the liquid immersion exposure, from the viewpoint that the immersionliquid needs to move on a wafer following the movement of an exposurehead that is scanning the wafer at a high speed and forming an exposurepattern, the contact angle of the immersion liquid with respect to thetopcoat in a dynamic state is important, and in order to obtain betterresist performance, it is preferable that the immersion liquid has areceding contact angle in the range.

During the release of the topcoat, an organic developer may be used, andanother release agent may be separately used. As the release agent, asolvent hardly permeating the resist film is preferable. From theviewpoint that the release of the topcoat can be carried out at the sametime as the development of the resist film, the topcoat is preferablyreleasable by an organic developer. The organic developer used for therelease is not particularly limited as long as it makes it possible todissolve and remove a less exposed area of the resist film.

From the viewpoint of the release with the organic developer, thedissolution rate of the topcoat in the organic developer is preferably 1to 300 nm/sec, and more preferably 10 to 100 nm/sec.

Here, the dissolution rate of the topcoat in the organic developer is afilm thickness decreasing rate in a case where the topcoat is exposed toa developer after film formation, and in the present invention, it is arate in a case where the topcoat is dipped in butyl acetate at 23° C.

An effect of reducing development defects after developing a resist filmis accomplished by adjusting the dissolution rate of a topcoat in anorganic developer to 1/sec or more, and preferably 10 nm/sec or more.Further, by setting the dissolution rate to 300 nm/sec or less, andpreferably 100 nm/sec, an effect that the line edge roughness of apattern after the development of the resist film is improved isaccomplished, possibly due to an effect of reducing the exposureunevenness during the liquid immersion exposure.

The topcoat may be removed using another known developer, for example,an aqueous alkali solution. Specific examples of the usable aqueousalkali solution include an aqueous tetramethylammonium hydroxidesolution.

[Pattern Forming Method]

The present invention also relates to a pattern forming method includinga resist film forming step of forming a resist film using the actinicray-sensitive or radiation-sensitive resin composition of the embodimentof the present invention, an exposing step of exposing the resist film,and a developing step of developing the exposed resist film using adeveloper.

In the present invention, the exposure is preferably carried out usingelectron beams, an ArF excimer laser, or extreme ultraviolet rays, andmore preferably electron beams or extreme ultraviolet rays.

For exposure (pattern forming step) on a resist film in the productionof a precision integrated circuit element, first, irradiation with anArF excimer laser, electron beams, or extreme ultraviolet rays (EUV) isperformed patternwise on the resist film of the present invention. In acase of the ArF excimer laser, the exposure dose is approximately 1 to100 mJ/cm², preferably approximately 20 to 60 mJ/cm²; in a case of theelectron beams, the exposure dose is approximately 0.1 to 20 μC/cm², andpreferably approximately 3 to 10 μC/cm²; and in a case of the extremeultraviolet rays, the exposure dose is approximately 0.1 to 20 mJ/cm²,and preferably approximately 3 to 15 mJ/cm².

Subsequently, post-exposure baking is performed on a hot plate,preferably at 60° C. to 150° C. for 5 seconds to 20 minutes, morepreferably at 80° C. to 120° C. for 15 seconds to 10 minutes, and stillmore preferably at 80° C. to 120° C. for 1 to 10 minutes, and thendevelopment, rinsing, and drying are performed to form a pattern. Here,the post-exposure baking is appropriately adjusted depending on the aciddecomposability of the repeating unit having an acid-decomposable groupin the resin (A). In a case where the acid decomposability is low, it isalso preferable that the temperature for post-exposure baking is 110° C.or higher and the heating time is 45 seconds or longer.

The developer is appropriately selected, but an alkali developer(typically an aqueous alkali solution) or a developer containing anorganic solvent (also referred to as an organic developer) is preferablyused. In a case where the developer is an aqueous alkali solution,development is performed with an aqueous alkali solution oftetramethylammonium hydroxide (TMAH), tetrabutylammonium hydroxide(TBAH), or the like at 0.1% to 5% by mass, and preferably 2% to 3% bymass for 0.1 to 3 minutes, and preferably 0.5 to 2 minutes by anordinary method such as a dip method, a puddle method, a spray method,or the like. An appropriate amount of an alcohol and/or a surfactant maybe added to the alkali developer. Thus, in the formation of a negativetone pattern, the film in the unexposed area is dissolved and theexposed area is hardly dissolved in the developer; and in the formationof a positive tone pattern, the film in the exposed area is dissolvedand the film in the unexposed area is hardly dissolved in the developer,so that a desired pattern is formed on the substrate.

In a case where the pattern forming method of the embodiment of thepresent invention has a step of performing development using an alkalideveloper, as the alkali developer, for example, an aqueous alkalisolution of inorganic alkalis such as sodium hydroxide, potassiumhydroxide, sodium carbonate, sodium silicate, sodium metasilicate, andaqueous ammonia, primary amines such as ethylamine and n-propylamine,secondary amines such as diethylamine and di-n-butylamine, tertiaryamines such as triethylamine and methyldiethylamine, alcohol amines suchas dimethylethanolamine and triethanolamine, tetraalkylammoniumhydroxides such as tetramethylammonium hydroxide, tetraethylammoniumhydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide,tetrapentylammonium hydroxide, tetrahexylammonium hydroxide,tetraoctylammonium hydroxide, ethyltrimethylammonium hydroxide,butyltrimethylammonium hydroxide, methyltriamylammonium hydroxide, anddibutyldipentylammonium hydroxide, quaternary ammonium salts such astrimethylphenylammonium hydroxide, trimethylbenzylammonium hydroxide,triethylbenzylammonium hydroxide, anddimethylbis(2-hydroxyethyl)ammonium hydroxide, or cyclic amines such aspyrrole and piperidine can be used.

Further, it is also possible to use a developer by adding an appropriateamount of alcohols or a surfactant to the aqueous alkali solution.

The alkali concentration of the alkali developer is usually 0.1% to 20%by mass.

The pH of the alkali developer is usually 10.0 to 15.0.

In particular, a 2.38%-by-mass aqueous tetramethylammonium hydroxidesolution is desirable.

Pure water may be used as the rinsing liquid in the rinse treatmentperformed after the alkali development, and an appropriate amount of asurfactant may be added to the pure water.

In addition, after the developing treatment or the rinsing treatment, atreatment of removing the developer or the rinsing liquid adhering to apattern with a supercritical fluid can be performed.

In a case where the pattern forming method of the embodiment of thepresent invention has a step of performing development using a developercontaining an organic solvent, as the developer in the step (hereinafteralso referred to as an organic developer), a polar solvent such as aketone-based solvent, an ester-based solvent, an alcohol-based solvent,an amide-based solvent, and an ether-based solvent, or ahydrocarbon-based solvent can be used.

In the present invention, the ester-based solvent is a solvent having anester group in the molecule, the ketone-based solvent is a solventhaving a ketone group in the molecule, the alcohol-based solvent is asolvent having an alcoholic hydroxyl group in the molecule, theamide-based solvent is a solvent having an amido group in the molecule,and the ether-based solvent is a solvent having an ether bond in themolecule. Among those, a solvent having a plurality of the functionalgroups in one molecule is also present, but in this case, it isapplicable to any of solvent species including the functional groupcontained in the solvent. For example, diethylene glycol monomethylether is applicable to any of the alcohol-based solvent and theether-based solvent in the classification. In addition, thehydrocarbon-based solvent is a hydrocarbon solvent having nosubstituent.

In particular, a developer containing at least one solvent selected fromthe ketone-based solvent, the ester-based solvent, the alcohol-basedsolvent, or the ether-based solvent is preferable.

It is preferable to use an ester-based solvent having 7 or more carbonatoms (preferably 7 to 14 carbon atoms, more preferably 7 to 12 carbonatoms, and still more preferably 7 to 10 carbon atoms), and 2 or lessheteroatoms as the developer from the viewpoint that the swelling of theresist film can be suppressed.

The heteroatom of the ester-based solvent is an atom other than a carbonatom and a hydrogen atom, and examples thereof include an oxygen atom, anitrogen atom, and a sulfur atom. The number of the heteroatoms ispreferably 2 or less.

Preferred examples of the ester-based solvents having 7 or more carbonatoms and 2 or less heteroatoms include amyl acetate, isoamyl acetate,2-methylbutyl acetate, 1-methylbutyl acetate, hexyl acetate, pentylpropionate, hexyl propionate, heptyl propionate, butyl butanoate, andisobutyl isobutanoate, and isoamyl acetate or isobutyl isobutanoate isparticularly preferably used.

As the developer, a mixed solvent of the ester-based solvent and thehydrocarbon-based solvent or a mixed solvent of the ketone-based solventand the hydrocarbon-based solvent may be used instead of the ester-basedsolvent having 7 or more carbon atoms and having 2 or less heteroatoms.Also in this case, it is effective in suppressing the swelling of theresist film.

In a case where the ester-based solvent and the hydrocarbon-basedsolvent are used in combination, it is preferable to use isoamyl acetateas the ester-based solvent. In addition, from the viewpoint of adjustingthe solubility of the resist film, a saturated hydrocarbon solvent (forexample, octane, nonane, decane, dodecane, undecane, and hexadecane) ispreferably used as the hydrocarbon-based solvent.

Examples of the ketone-based solvent include 1-octanone, 2-octanone,1-nonanone, 2-nonanone, acetone, 2-heptanone (methyl amyl ketone),4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone,2,5-dimethyl-4-hexanone, diisobutyl ketone, cyclohexanone,methylcyclohexanone, phenyl acetone, methyl ethyl ketone, methylisobutyl ketone, acetyl acetone, acetonyl acetone, ionone, diacetonylalcohol, acetyl carbinol, acetophenone, methyl naphthyl ketone,isophorone, and propylene carbonate, and diisobutyl ketone and2,5-dimethyl-4-hexanone are particularly preferably used.

Examples of the ester-based solvent include methyl acetate, butylacetate, ethyl acetate, isopropyl acetate, pentyl acetate, isoamylacetate, amyl acetate, propylene glycol monomethyl ether acetate,ethylene glycol monoethyl ether acetate, diethylene glycol monobutylether acetate, diethylene glycol monoethyl ether acetate,ethyl-3-ethoxypropionate, 3-methoxybutyl acetate,3-methyl-3-methoxybutyl acetate, methyl formate, ethyl formate, butylformate, propyl formate, ethyl lactate, butyl lactate, propyl lactate,butyl butyrate, and methyl 2-hydroxyisobutyrate.

Examples of the alcohol-based solvent include alcohols such as methylalcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butylalcohol, sec-butyl alcohol, 4-methyl-2-pentanol, tert-butyl alcohol,isobutyl alcohol, n-hexyl alcohol, n-heptyl alcohol, n-octyl alcohol,and n-decanol, glycol-based solvents such as ethylene glycol, diethyleneglycol, and triethylene glycol; and glycol ether-based solvents such asethylene glycol monomethyl ether, propylene glycol monomethyl ether,ethylene glycol monoethyl ether, propylene glycol monoethyl ether,diethylene glycol monomethyl ether, triethylene glycol monoethyl ether,and methoxymethyl butanol.

Examples of the ether-based solvent include anisole, dioxane, andtetrahydrofuran, in addition to the glycol ether-based solvents.

As the amide-based solvent, for example, N-methyl-2-pyrrolidone,N,N-dimethylacetamide, N,N-dimethylformamide, hexamethylphosphorictriamide, 1,3-dimethyl-2-imidazolidinone, or the like can be used.

Examples of the hydrocarbon-based solvent include aromatichydrocarbon-based solvents such as toluene and xylene, and aliphatichydrocarbon-based solvents such as pentane, hexane, octane, decane, andundecane.

In addition, the aliphatic hydrocarbon-based solvent which is ahydrocarbon-based solvent may be a mixture of compounds having the samenumber of carbon atoms but different structures. For example, in a casewhere decane is used as the aliphatic hydrocarbon-based solvent,2-methylnonane, 2,2-dimethyloctane, 4-ethyloctane, isooctane, or thelike which is a compound having the same number of carbon atoms anddifferent structures, may be included in the aliphatic hydrocarbon-basedsolvent.

In addition, only one kind or a plurality of kinds of the compounds asdescribed above having the same number of carbon atoms and differentstructures may be included.

A plurality of the solvents may be mixed or the solvent may be used inadmixture with a solvent other than those described above or water.However, in order to fully exert the effects of the present invention,the moisture content of the developer as a whole is preferably less than10% by mass, and the developer is more preferably substantially free ofthe moisture.

The concentration of the organic solvent (in a case of mixing aplurality of the organic solvents, a total thereof) in the organicdeveloper is preferably 50% by mass or more, more preferably 50% to 100%by mass, still more preferably 85% to 100% by mass, even still morepreferably 90% to 100% by mass, and particularly preferably 95% to 100%by mass. Most preferably, the organic solvent consists substantiallyonly of an organic solvent. In addition, a case of consistingsubstantially only of an organic solvent includes a case of containing atrace amount of a surfactant, an antioxidant, a stabilizer, anantifoaming agent, or the like.

In particular, the organic developer is preferably a developercontaining at least one organic solvent selected from the groupconsisting of a ketone-based solvent, an ester-based solvent, analcohol-based solvent, an amide-based solvent, and an ether-basedsolvent.

The vapor pressure of the organic developer at 20° C. is preferably 5kPa or less, more preferably 3 kPa or less, and particularly preferably2 kPa or less. By setting the vapor pressure of the organic developer to5 kPa or less, evaporation of the developer on the substrate or in thedevelopment cup is suppressed, the temperature uniformity in a waferplane is improved, and as a result, the dimensional uniformity in thewafer plane is improved.

Specific examples of the organic developer having a vapor pressure of 5kPa or less include ketone-based solvents such as 1-octanone,2-octanone, 1-nonanone, 2-nonanone, 2-heptanone (methyl amyl ketone),4-heptanone, 2-hexanone, diisobutyl ketone, cyclohexanone,methylcyclohexanone, phenylacetone, and methyl isobutyl ketone,ester-based solvents such as butyl acetate, pentyl acetate, isoamylacetate, amyl acetate, propylene glycol monomethyl ether acetate,ethylene glycol monoethyl ether acetate, diethylene glycol monobutylether acetate, diethylene glycol monoethyl ether acetate,ethyl-3-ethoxypropionate, 3-methoxybutyl acetate,3-methyl-3-methoxybutyl acetate, butyl formate, propyl formate, ethyllactate, butyl lactate, and propyl lactate, alcohol-based solvents suchas n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butylalcohol, tert-butyl alcohol, isobutyl alcohol, n-hexyl alcohol, n-heptylalcohol, n-octyl alcohol, and n-decanol, glycol-based solvents such asethylene glycol, diethylene glycol, and triethylene glycol, glycolether-based solvents such as ethylene glycol monomethyl ether, propyleneglycol monomethyl ether, ethylene glycol monoethyl ether, propyleneglycol monoethyl ether, diethylene glycol monomethyl ether, triethyleneglycol monoethyl ether, and methoxymethyl butanol, ether-based solventssuch as tetrahydrofuran, amide-based solvents such asN-methyl-2-pyrrolidone, N,N-dimethylacetamide, andN,N-dimethylformamide, aromatic hydrocarbon-based solvents such astoluene and xylene, and aliphatic hydrocarbon-based solvents such asoctane and decane.

Specific examples of the organic developer having a vapor pressure of 2kPa or less, which is a particularly preferable range, includeketone-based solvents such as 1-octanone, 2-octanone, 1-nonanone,2-nonanone, 2-heptanone, 4-heptanone, 2-hexanone, diisobutyl ketone,cyclohexanone, methylcyclohexanone, and phenylacetone, ester-basedsolvents such as butyl acetate, amyl acetate, propylene glycolmonomethyl ether acetate, ethylene glycol monoethyl ether acetate,diethylene glycol monobutyl ether acetate, diethylene glycol monoethylether acetate, ethyl-3-ethoxypropionate, 3-methoxybutyl acetate,3-methyl-3-methoxybutyl acetate, ethyl lactate, butyl lactate, andpropyl lactate, alcohol-based solvents such as n-butyl alcohol,sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-hexylalcohol, n-heptyl alcohol, n-octyl alcohol, and n-decanol, glycol-basedsolvents such as ethylene glycol, diethylene glycol, and triethyleneglycol, glycol ether-based solvents such as ethylene glycol monomethylether, propylene glycol monomethyl ether, ethylene glycol monoethylether, propylene glycol monoethyl ether, diethylene glycol monomethylether, triethylene glycol monoethyl ether, and methoxymethyl butanol,amide-based solvents such as N-methyl-2-pyrrolidone,N,N-dimethylacetamide, and N,N-dimethylformamide, aromatichydrocarbon-based solvents such as xylene, and aliphatichydrocarbon-based solvents such as octane, decane, and undecane.

The organic developer may include a basic compound. Specific examplesand preferred examples of the basic compound which can be included inthe developer used in the present invention are the same ones as thosein the basic compound which can be included in the above-describedactinic ray-sensitive or radiation-sensitive resin composition.

An appropriate amount of a surfactant can be added to the organicdeveloper, as necessary.

The surfactant is not particularly limited, but, for example, an ionicor nonionic fluorine-based and/or silicon-based surfactant or the likecan be used. Examples of such the fluorine- and/or silicon-basedsurfactant include the surfactants described in, for example,JP1987-036663A (JP-S62-036663A), JP1986-226746A (JP-S61-226746A),JP1986-226745A (JP-S61-226745A), JP1987-170950A (JP-S62-170950A),JP1988-034540A (JP-S63-034540A), JP1995-230165A (JP-H07-230165A),JP1996-062834A (JP-H08-062834A), JP1997-054432A (JP-H09-054432A),JP1997-005988A (JP-H09-005988A), U.S. Pat. Nos. 5,405,720A, 5,360,692A,5,529,881A, 5,296,330A, 5,436,098A, 5,576,143A, 5,294,511A, and5,824,451A, and non-ionic surfactants are preferable. The non-ionicsurfactant is not particularly limited, but it is more preferable to usea fluorine-based surfactant or a silicon-based surfactant.

The amount of the surfactant to be used is preferably 0.0001% to 2% bymass, more preferably 0.0001% to 1% by mass, and particularly preferably0.0001% to 0.1% by mass, with respect to the total amount of thedeveloper.

As the developing method, for example, a method in which a substrate isdipped in a tank filled with a developer for a certain period of time (adip method), a method in which development is performed by heaping adeveloper up onto the surface of a substrate by surface tension, andthen leaving it to stand for a certain period of time (a puddle method),a method in which a developer is sprayed on the surface of a substrate(a spray method), a method in which a developer is continuously jettedonto a substrate rotating at a constant speed while scanning a developerjetting nozzle at a constant rate (a dynamic dispense method), or thelike can be applied.

In a case where the various developing methods include a step of jettinga developer from developing nozzles of a developing device toward theresist film, the jetting pressure of the developer to be jetted (flowrate per unit area of the developer to be jetted) is preferably 2mL/sec/mm² or less, more preferably 1.5 mL/sec/mm² or less, and stillmore preferably 1 mL/sec/mm² or less. There is no particular lower limitto the flow rate, but the lower limit is 0.2 mL/sec/mm² or more inconsideration of a throughput.

By setting the jetting pressure of the developer to be jetted within therange, it is possible to significantly reduce the pattern defectsderived from resist residues after development.

Although the details of this mechanism are not clear, it is consideredthat by setting the jetting pressure to be in the range, the pressureapplied to the resist film by the developer is likely to be reduced andthe resist film/pattern is prevented from being scraped or brokencarelessly.

In addition, the jetting pressure (mL/sec/mm²) of the developer is avalue at the outlet of the developing nozzle in the developing device.

Examples of the method of adjusting the jetting pressure of thedeveloper include a method of adjusting a jetting pressure with a pumpor the like, and a method of changing a pressure by adjusting thepressure with a supply from a pressure tank.

Furthermore, after a step of performing development using a developerincluding an organic solvent, a step of stopping the development may becarried out while substituting the solvent with another solvent.

A step of performing washing using a rinsing liquid may be includedafter the step of performing development using a developer including anorganic solvent, but from the viewpoint of a throughput (productivity),an amount of the rinsing liquid to be used, and the like, a step ofperforming washing using a rinsing liquid may not be included.

The rinsing liquid used in the rinsing step after the developing stepusing a developer including an organic solvent is not particularlylimited as long as the rinsing liquid does not dissolve the resistpattern, and a solution including a common organic solvent can be used.As the rinsing liquid, a rinsing liquid containing at least one organicsolvent selected from the group consisting of a hydrocarbon-basedsolvent, a ketone-based solvent, an ester-based solvent, analcohol-based solvent, an amide-based solvent, and an ether-basedsolvent is preferably used.

Specific examples of the hydrocarbon-based solvent, the ketone-basedsolvent, the ester-based solvent, the alcohol-based solvent, theamide-based solvent, and the ether-based solvent include the same onesas those described for the developer including an organic solvent, andin particular, suitable examples thereof include butyl acetate andmethyl isobutyl carbinol.

It is preferable to perform a step of performing washing, morepreferably using a rinsing liquid containing at least one organicsolvent selected from the group consisting of an ester-based solvent, analcohol-based solvent, and a hydrocarbon-based solvent, and still morepreferably using a rinsing liquid containing the alcohol-based solventor the hydrocarbon-based solvent, after the step of performingdevelopment using a developer including an organic solvent.

Among the organic solvents, the hydrocarbon-based solvent is alsopreferably used, and the aliphatic hydrocarbon-based solvent is morepreferably used, as the organic solvent included in the rinsing liquid.As the aliphatic hydrocarbon-based solvent used in the rinsing liquid,from the viewpoint of further improving the effects, an aliphatichydrocarbon-based solvent having 5 or more carbon atoms (for example,pentane, hexane, octane, decane, undecane, dodecane, and hexadecane) ispreferable, an aliphatic hydrocarbon-based solvent having 8 or morecarbon atoms is more preferable, and an aliphatic hydrocarbon-basedsolvent having 10 or more carbon atoms is still more preferable.

Incidentally, the upper limit value of the number of carbon atoms in thealiphatic hydrocarbon-based solvent is not particularly limited, and forexample, is 16 or less, preferably 14 or less, and more preferably 12 orless.

Among the aliphatic hydrocarbon-based solvents, decane, undecane, ordodecane is particularly preferable, and undecane is the mostpreferable.

By using the hydrocarbon-based solvent (in particular, the aliphatichydrocarbon-based solvent) as the organic solvent included in therinsing liquid as described above, the developer permeating into theresist film slightly after development is washed away, the swelling isfurther suppressed, and thus, an effect of suppressing pattern collapseis further exhibited.

The respective components in a plural number may be mixed or thecomponents may also be used in admixture with an organic solvent otherthan the solvents.

The moisture content of the rinsing liquid is preferably 10% by mass orless, more preferably 5% by mass or less, and particularly preferably 3%by mass or less. By setting the moisture content to 10% by mass or less,good development characteristics can be obtained.

The vapor pressure at 20° C. of the rinsing liquid which is used afterthe step of performing development using a developer including anorganic solvent is preferably from 0.05 kPa to 5 kPa, more preferablyfrom 0.1 kPa to 5 kPa, and most preferably from 0.12 kPa to 3 kPa. Bysetting the vapor pressure of the rinsing liquid to be from 0.05 kPa to5 kPa, the temperature uniformity in a wafer plane is improved, andfurther, the dimensional uniformity in a wafer plane is enhanced bysuppression of swelling due to the permeation of the rinsing liquid.

The rinsing liquid can be used after an appropriate amount of asurfactant is added thereto.

In the rinsing step, a wafer which has been developed using a developerincluding an organic solvent is subjected to a washing treatment using arinsing liquid including an organic solvent. A method for the washingtreatment is not particularly limited, for example, a method in which arinsing liquid is continuously jetted on a substrate rotating at aconstant speed (a rotation application method), a method in which asubstrate is dipped in a tank filled with a rinsing liquid for a certainperiod of time (a dip method), a method in which a rinsing liquid issprayed on a substrate surface (a spray method), or the like, and amongthese, a method in which a washing treatment is performed using therotation application method, and a substrate is rotated at a rotationspeed of 2,000 rpm to 4,000 rpm after washing, thereby removing therinsing liquid from the substrate, is preferable. Further, it is alsopreferable that a heating step (postbaking) is included after therinsing step. The developer and the rinsing liquid remaining between andinside the patterns are removed by the baking. The heating step afterthe rinsing step is performed, usually at 40° C. to 160° C., andpreferably 70° C. to 95° C., usually for 10 seconds to 3 minutes, andpreferably for 30 seconds to 90 seconds.

In a case where there is no step of performing washing with a rinsingliquid, for example, the development treatment method described inparagraphs [0014] to [0086] of JP2015-216403A can be adopted.

Moreover, the pattern forming method of the embodiment of the presentinvention may include a developing step using an organic developer and adeveloping step using an alkali developer. A portion having a lowexposure intensity is removed by development using an organic developer,and a portion having a high exposure intensity is removed by performingdevelopment using an alkali developer. By virtue of multiple developmentprocesses in which development is performed in a plurality of times insuch a manner, a pattern can be formed by keeping only a region with anintermediate exposure intensity from not being dissolved, so that afiner pattern than usual can be formed (the same mechanism as in [0077]of JP2008-292975A).

It is preferable that various materials (for example, a resist solvent,a developer, a rinsing liquid, a composition for forming anantireflection film, and a composition for forming a topcoat) used inthe actinic ray-sensitive or radiation-sensitive resin composition inthe embodiment of the present invention, and the pattern forming methodof the embodiment of the present invention include no impurities such asmetals, metal salts including halogen, acids, alkalis, and componentsincluding a sulfur atom or a phosphorus atom. Here, examples of theimpurities including a metal atom include Na, K, Ca, Fe, Cu, Mn, Mg, Al,Cr, Ni, Zn, Ag, Sn, Pb, Li, and salts thereof.

The content of the impurities included in these materials is preferably1 ppm or less, more preferably 1 ppb or less, still more preferably 100ppt or less, and particularly preferably 10 ppt or less, and it is themost preferable that substantially no metal component is included (belowa detection limit of the measuring apparatus).

Examples of a method for removing impurities such as metals from thevarious materials include filtration using a filter. As for the filterpore diameter, the pore size is preferably 10 nm or less, morepreferably 5 nm or less, and still more preferably 3 nm or less. As forthe materials of a filter, a filter made of polytetrafluoroethylene,polyethylene, nylon, or the like is preferable. The filter may be acomposite material in which these materials are combined with an ionexchange medium. As the filter, a filter which has been washed with anorganic solvent in advance may be used. In the step of filtration usinga filter, a plurality of kinds of filters linked in series or inparallel may be used. In a case of using a plurality of kinds offilters, a combination of filters having different pore diameters and/ormaterials may be used. In addition, various materials may be filteredplural times, and the step of filtering plural times may be acirculating filtration step.

In addition, examples of the method for reducing the impurities such asa metal included in various materials include a method of selecting rawmaterials having a low content of metals as raw materials constitutingvarious materials, a method of subjecting raw materials constitutingvarious materials to filtration using a filter, and a method ofperforming distillation under the condition for suppressing thecontamination as much as possible by, for example, lining the inside ofa device with TEFLON (registered trademark). Preferred conditions forthe filtration using a filter performed on the raw materialsconstituting various materials are the same ones as the above-mentionedconditions.

In addition to the filtration using a filter, removal of impurities byan adsorbing material may be performed, or a combination of filtrationusing a filter and an adsorbing material may be used. As the adsorbingmaterial, known adsorbing materials can be used, and for example,inorganic adsorbing materials such as silica gel and zeolite, andorganic adsorbing materials such as activated carbon can be used.

In addition, as a method for reducing the impurities such as metalsincluded in various materials, a method in which a raw material having alow metal content is selected as a raw material constituting variousmaterials, the raw material constituting the various materials issubjected to filtration using a filter; distillation under conditionssuppressing contamination as much as possible by performing a liningwith TEFLON (registered trademark) in the inside of a device; or thelike. Preferred conditions for the filtration using a filter performedon the raw materials constituting various materials are the same ones asthe above-mentioned conditions.

In addition to the filtration using a filter, removal of impurities byan adsorbing material may be performed, or a combination of filtrationusing a filter and an adsorbing material may be used. As the adsorbingmaterial, known adsorbing materials can be used, and for example,inorganic adsorbing materials such as silica gel and zeolite, andorganic adsorbing materials such as activated carbon can be used.

[Storage Container]

As an organic solvent (also referred to as an “organic treatmentliquid”) which can be used for a developer and a rinsing liquid, it ispreferable to use one stored in a storage container for storing anorganic treatment liquid for patterning a chemically amplified ornon-chemically amplified resist film, in which the container has astorage part. The storage container is preferably, for example, astorage container for storing an organic treatment liquid for patterninga resist film, in which the inner wall of the storage part being incontact with the organic treatment liquid is formed from a resindifferent from any of a polyethylene resin, a polypropylene resin, and apolyethylene-polypropylene resin, or of a metal subjected to a rustprevention/metal elution prevention treatment. An organic solvent to beused as an organic treatment liquid for patterning a resist film isstored in the storage part of the storage container, and the organicsolvent jetted from the storage part can be used at the time ofpatterning the resist film.

In a case where the storage container further has a sealing part forsealing the storage part, the sealing part is also preferably formed ofa resin different from one or more resins selected from the groupconsisting of a polyethylene resin, a polypropylene resin, and apolyethylene-polypropylene resin, or of a metal which has been subjectedto a rust prevention/metal elution prevention treatment.

Here, the sealing part refers to a member capable of shielding thestorage part from the outside air, and suitable examples thereof includea packing and an O ring.

The resin different from one or more resins selected from the groupconsisting of a polyethylene resin, a polypropylene resin, and apolyethylene-polypropylene resin is preferably a perfluoro resin.

Examples of the perfluoro resin include a tetrafluoroethylene resin(PTFE), a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin(PFA), a tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP),a tetrafluoroethylene-ethylene copolymer resin (ETFE), atrifluoroethylene chloride-ethylene copolymer resin (ECTFE), apolyvinylidene fluoride resin (PVDF), a trifluoroethylene chloride resin(PCTFE), and a polyvinyl fluoride resin (PVF).

Particularly preferred examples of the perfluoro resin include atetrafluoroethylene resin, a tetrafluoroethylene-perfluoroalkyl vinylether copolymer, and a tetrafluoroethylene-hexafluoropropylene copolymerresin.

Examples of the metal in the metal which has been subjected to a rustprevention/metal elution prevention treatment include carbon steel,alloy steel, nickel chromium steel, nickel chromium molybdenum steel,chromium steel, chromium molybdenum steel, and manganese steel.

As the rust prevention/metal elution prevention treatment, a coatingtechnique can be applied.

The coating technique is roughly divided into three types of metalcoating (various plating), inorganic coating (various chemicalconversion treatments, glass, concrete, ceramics, and the like), andorganic coating (a rust preventive oil, a paint, rubber, and plastics).

Preferred examples of the coating technique include a rust preventiveoil, a rust inhibitor, a corrosion inhibitor, a chelate compound, astrippable plastic, and a surface treatment with a lining agent.

Among those, corrosion inhibitors, such as various chromates, nitrites,silicates, phosphates, oleic acid, dimer acid, carboxylic acids such asnaphthenic acid, carboxylic acid metal soaps, sulfonates, amine salts,and esters (glycerol esters of higher fatty acids and phosphoric acidesters), chelate compounds such as ethylene diamine tetraacetic acid,gluconic acid, nitrilotriacetic acid, hydroxyethyl ethylene diaminetriacetic acid, and diethylene triamine pentaacetic acid, and a fluorineresin lining are preferable. A phosphate treatment and the fluorineresin lining are particularly preferable.

Although it does not directly prevent rust as compared with a directcoating treatment, it is also preferable to adopt a “pretreatment” whichis a step prior to a rust prevention treatment, as a treatment methodleading to prolongation of the rust prevention period by a coatingtreatment.

As a specific example of such a pretreatment, a treatment for removing avariety of corrosive factors such as chlorides and sulfates present onthe metal surface by washing or polishing can be suitably mentioned.

Specific examples of the storage container include the following ones.

-   -   FluoroPurePFA composite drum manufactured by Entegris Inc.        (wetted inner surface; PFA resin lining)        -   Steel drum manufactured by JFE Corporation (wetted inner            surface; zinc phosphate-coated film)

Furthermore, examples of the storage container which can be used in thepresent invention include the containers described in paragraphs [0013]to [0030] of JP1999-021393A (JP-H11-021393A) and paragraphs [0012] to[0024] of JP1998-045961A (JP-H10-045961A).

In order to prevent breakdown of a chemical liquid pipe and variousparts (a filter, an O-ring, a tube, and the like) due to electrostaticcharging and subsequent electrostatic discharging, a conductive compoundmay be added to the organic treatment liquid of the present invention.The conductive compound is not particularly limited, but examplesthereof include methanol. The addition amount of the conductive compoundis not particularly limited, but is preferably 10% by mass or less, andmore preferably 5% by mass or less from the viewpoint of maintainingpreferable development characteristics. With regard to the members ofthe chemical liquid pipe, it is possible to use various pipes coatedwith stainless steel (SUS), or a polyethylene resin, a polypropyleneresin, or a fluorine resin (a polytetrafluoroethylene resin, aperfluoroalkoxy resin, or the like), which has been subjected to anantistatic treatment. Similarly, a polyethylene resin, a polypropyleneresin, or a fluorine resin (a polytetrafluoroethylene resin, aperfluoroalkoxy resin, or the like), which has been subjected to anantistatic treatment, can be used for a filter and an O-ring.

Moreover, generally, the developer and the rinsing liquid are stored ina waste liquid tank through a pipe after use. At that time, in a casewhere a hydrocarbon-based solvent is used as the rinsing liquid, thereis a method of passing a solvent in which a resist is dissolved througha pipe again in order to prevent the resist dissolved in the developerfrom being precipitated and adhering to the back surface of the wafer,the side surface of the pipe or the like. Examples of the method ofpassing the solvent through the pipe include a method in which the backsurface, the side surface, and the like of a substrate are washed with asolvent in which a resist is dissolved and then the solvent is allowedto flow after performing washing with a rinsing liquid, and a method offlowing a solvent in which a resist is dissolved so as to pass through apipe while being not in contact with the resist.

The solvent to be passed through the pipe is not particularly limited aslong as it can dissolve the resist, examples thereof include theabove-mentioned organic solvents, and propylene glycol monomethyl etheracetate (PGMEA), propylene glycol monoethyl ether acetate, propyleneglycol monopropyl ether acetate, propylene glycol monobutyl etheracetate, propylene glycol monomethyl ether propionate, propylene glycolmonoethyl ether propionate, ethylene glycol monomethyl ether acetate,ethylene glycol monoethyl ether acetate, propylene glycol monomethylether (PGME), propylene glycol monoethyl ether, propylene glycolmonopropyl ether, propylene glycol monobutyl ether, ethylene glycolmonomethyl ether, ethylene glycol monoethyl ether, 2-heptatone, ethyllactate, 1-propanol, acetone, or the like can be used. Among those,PGMEA, PGME, or cyclohexanone can be preferably used.

[Photo Mask]

Furthermore, the present invention also relates to a photo maskmanufactured using the above-described pattern forming method. The photomask manufactured using the above-described pattern forming method maybe a light transmission type mask used in an ArF excimer laser or thelike, or may be a light reflective type mask used in reflectivelithography using EUV light as a light source.

[Method for Manufacturing Electronic Device]

Moreover, the present invention further relates to a method formanufacturing an electronic device, the method including theabove-described pattern forming method. The electronic devicemanufactured by the method for manufacturing an electronic device of anembodiment of the present invention is suitably mounted on electric orelectronic equipment (for example, home electronics, office automation(OA)-related equipment, media-related equipment, optical equipment, andtelecommunication equipment).

EXAMPLES

Hereinbelow, the present invention will be described in more detail withreference to Examples. The materials, the amounts of materials used, theproportions, the treatment details, the treatment procedure, and thelike shown in Examples below may be modified as appropriate as long asthe modifications do not depart from the spirit of the presentinvention. Therefore, the scope of the present invention should not beconstrued as being limited to Examples shown below.

<Solvent>

(Synthesis of Ethyl Lactates 1 to 5)

Glucose was lactic acid-fermented with lactic acid bacteria, and theobtained lactic acid was subjected ethyl esterification to obtain ethyllactates 1 to 5, respectively.

(Synthesis of Ethyl Lactate C1)

Lactic acid nitrile was synthesized from acetaldehyde and hydrogencyanide, and hydrolyzed to obtain lactic acid. The lactic acid obtainedabove was ethyl-esterified to obtain an ethyl lactate C1.

The specific compositions of the obtained ethyl lactates 1 to 5 andethyl lactate C1 are described below. The ratio of L isomer and theratio of D isomer of each ethyl lactate are mass ratios.

Ethyl lactate 1: (ratio of L isomer: 90%, ratio of D isomer: 10%)

Ethyl lactate 2: (ratio of L isomer: 62%, ratio of D isomer: 38%)

Ethyl lactate 3: (ratio of L isomer: 53%, ratio of D isomer: 47%)

Ethyl lactate 4: (ratio of L isomer: 41%, ratio of D isomer: 59%)

Ethyl lactate 5: (ratio of L isomer: 8%, ratio of D isomer: 92%)

Ethyl lactate C1: (ratio of L isomer: 50%, ratio of D isomer: 50%)

Furthermore, ethyl lactates 6 to 8 were synthesized in the same manneras the ethyl lactate 1. The specific compositions of the ethyl lactate 6to 8 are described below.

Ethyl lactate 6: (ratio of L isomer: 80%, ratio of D isomer: 20%)

Ethyl lactate 7: (ratio of L isomer: 85%, ratio of D isomer: 15%)

Ethyl lactate 8: (ratio of L isomer: 88%, ratio of D isomer: 12%)

Examples 1 to 5 and Comparative Example 1

The acetic acid content and the purity were measured as follows, usingthe ethyl lactates 1 to 5 and the ethyl lactate C1.

<Acetic Acid Content>

The acetic acid contents of the ethyl lactates 1 to 5 and the ethyllactate C1 were measured using ion chromatography (gas chromatographmass spectrometer GCMS-QP2010 manufactured by Shimadzu Corporation,which is connected to pyrolyzer PY2020D manufactured by FrontierLaboratories) (initial value (ppm)).

After storing the ethyl lactates 1 to 5 and the ethyl lactate C1 at 23°C. for 1 year, each of the acetic acid contents was measured using ionchromatography (gas chromatograph mass spectrometer GCMS-QP2010manufactured by Shimadzu Corporation, which is connected to pyrolyzerPY2020D manufactured by Frontier Laboratories) (acetic acid content(ppm) after a lapse of time).

The lower the value of “Acetic acid content (ppm) after lapse oftime−Initial value (ppm)”, the better the storage stability.

<Purity>

The purities of the ethyl lactates 1 to 5 and the ethyl lactate C1 weremeasured using gas chromatography (with a gas chromatograph massspectrometer GCMS-QP2010 manufactured by Shimadzu Corporation, which isconnected to pyrolyzer PY2020D manufactured by Frontier Laboratories)(initial value (%)).

After storing the ethyl lactates 1 to 5 and the ethyl lactate C1 at 23°C. for 1 year, each of the purities was measured using gaschromatography (gas chromatograph mass spectrometer GCMS-QP2010manufactured by Shimadzu Corporation, which is connected to pyrolyzerPY2020D manufactured by Frontier Laboratories) (purity (%) after a lapseof time).

The lower the value of “Purity (%) after lapse of time−Initial value(%)”, the better the storage stability.

The evaluation results of the acetic acid content and the purity areshown in Table 1 below.

TABLE 1 Acetic acid content Purity After lapse After lapse Ethyl Initialof time (23° Initial of time (23° lactate stage C., 1 year) stage C., 1year) Example 1 1  8 ppm  9 ppm 99.84% 99.82% Example 2 2 15 ppm 18 ppm99.79% 99.77% Example 3 3 20 ppm 22 ppm 99.81% 99.78% Example 4 4 12 ppm15 ppm 99.82% 99.80% Example 5 5 15 ppm 16 ppm 99.80% 99.79% ComparativeC1 30 ppm 100 ppm  99.81% 99.35% Example 1

As is clear from Table 1, it was found that the ethyl lactates 1 to 5had excellent storage stability, as compared with the ethyl lactate C1.

<Resin (A)>

The resins (P-1) to (P-7) used are shown below. The structure of therepeating unit and a content (molar ratio) thereof, a weight-averagemolecular weight (Mw), and a dispersity (Mw/Mn) of each resin are alsoshown.

(P-1)

Mw = 6000 Mw/Mn = 1.31 (P-2)

Mw = 6000 Mw/Mn = 1.36 (P-3)

Mw = 7500 Mw/Mn = 1.45 (P-4)

Mw = 6000 Mw/Mn = 1.65 (P-5)

Mw = 4500 Mw/Mn = 1.31 (P-6)

Mw = 15000 Mw/Mn = 1.82 (P-7)

Mw = 8000 Mw/Mn = 1.62

<Photoacid Generator>

The structures of the photoacid generators used are shown below.

The pKa's of acids produced from the photoacid generators (S-1) to (S-4)are from −10 to 5.

<Acid Diffusion Control Agent>

The structures of the acid diffusion control agents used are shownbelow.

<Solvent>

The solvents used are shown below.

EL1: Ethyl lactate 1

EL2: Ethyl lactate 2

EL3: Ethyl lactate 3

EL4: Ethyl lactate 4

EL5: Ethyl lactate 5

EL6: Ethyl lactate 6

EL7: Ethyl lactate 7

EL8: Ethyl lactate 8

ELC1: Ethyl lactate C1 (for Comparative Examples)

PGMEA: Propylene glycol monomethyl ether acetate

PGME: Propylene glycol monomethyl ether

Examples 101 to 116, and Comparative Examples 101 and 102 [Preparationand Coating of Coating Liquid of Resist Composition]

The components shown in Table 2 below were dissolved in a solvent shownin Table 2 below to prepare a solution having a concentration of solidcontents shown in Table 2 below, and this solution was filtered througha polyethylene filter having a pore size of 0.02 μm to obtain each ofresist compositions R-1 to R-16 and R-C1 to R-C2.

These resist compositions were applied onto a 6-inch Si wafer which hadbeen previously treated with hexamethyldisilazane (HMDS) using a spincoater Mark8 manufactured by Tokyo Electron, Limited, and dried on a hotplate at 130° C. for 300 seconds to obtain a resist film having a filmthickness of 100 nm.

Here, 1 inch is 0.0254 m.

In addition, even in a case where the Si wafer is changed to a chromiumsubstrate, the same results can be obtained.

[EB Exposure and Development]

A wafer on which the resist film obtained above had been applied wassubjected to patternwise irradiation using an electron beam drawingapparatus (HL750 manufactured by Hitachi, Ltd., accelerating voltage: 50KeV). At that time, drawing was performed so that a 1:1 line-and-spacewas formed. After performing electron beam drawing, the wafer was heatedon a hot plate at 100° C. for 60 seconds, puddled with a 2.38%-by-massaqueous tetramethylammonium hydroxide solution, developed for 30seconds, rinsed with pure water, then rotated at a rotation speed of4,000 rpm for 30 seconds, and then heated at 95° C. for 60 seconds toobtain a resist pattern with a 1:1 line-and-space pattern having a linewidth of 50 nm.

[Evaluation]

(1) Sensitivity

The cross-sectional shape of the obtained pattern was observed with ascanning electron microscope (S-4300 manufactured by Hitachi, Ltd.). Theexposure dose (electron beam irradiation dose) upon resolution of a 1:1line-and-space resist pattern having a line width of 50 nm was taken asa sensitivity (Eop) (sensitivity before a lapse of time).

The resist composition was stored at 23° C. for 1 year to form a resistpattern as described above, and the sensitivity was measured(sensitivity after a lapse of time).

(2) LS Resolving Power

A marginal resolving power (a minimum line width at which lines andspaces (line:space=1:1) are separated and resolved) at an exposure doseshowing the sensitivity was taken as an L/S resolving power (nm)(resolving power before a lapse of time).

The resist composition was stored at 23° C. for 1 year to form a resistpattern as described above, and the L/S resolving power was measured (LSresolving power after a lapse of time).

(3) Shape

The cross-sectional shape of the obtained pattern was observed using ascanning electron microscope (S-4300 manufactured by Hitachi, Ltd.)(shape before a lapse of time).

The resist composition was stored at 23° C. for 1 year to form a resistpattern as described above, and the shape was measured (shape after alapse of time).

Furthermore, in Table 2 below, the content (% by mass) of each componentother than the solvent means a content ratio with respect to the totalsolid content. In addition, the content ratio (% by mass) of the solventused with respect to all the solvents is described in Table 2 below.

The evaluation results are shown in Table 3.

TABLE 2 Resin Acid diffusion control agent Photoacid generator SolidSolid Solid Solvent Concentration (% Resist content ratio content ratiocontent ratio Concentration by mass) of total composition Type (% bymass) Type (% by mass) Type (% by mass) Type (% by mass) solid contentR-1 P-1 81.68 Q-1 4.65 S-1 13.67 EL1/PGME/PGMEA 50/20/30 2.6 R-2 P-181.68 Q-1 4.65 S-1 13.67 EL2/PGME/PGMEA 50/20/30 2.6 R-3 P-1 81.68 Q-14.65 S-1 13.67 EL3/PGME/PGMEA 50/20/30 2.6 R-4 P-1 81.68 Q-1 4.65 S-113.67 EL4/PGME/PGMEA 50/20/30 2.6 R-5 P-1 81.68 Q-1 4.65 S-1 13.67EL5/PGME/PGMEA 50/20/30 2.6 R-C1 P-1 81.68 Q-1 4.65 S-1 13.67ELC1/PGME/PGMEA 50/20/30 2.6 R-6 P-1 81.68 Q-1 4.65 S-1 13.67EL1/PGME/PGMEA 10/20/70 2.6 R-7 P-1 81.68 Q-1 4.65 S-1 13.67EL6/PGME/PGMEA 50/20/30 2.6 R-8 P-1 81.68 Q-1 4.65 S-1 13.67EL7/PGME/PGMEA 80/20/0  2.6 R-9 P-2 73.04 Q-2 8.76 S-2 18.20EL8/PGME/PGMEA 50/20/30 2.8 R-10 P-1 79.23 Q-3 4.65 S-2 16.12EL1/PGME/PGMEA 60/30/10 2.4 R-11 P-3 79.21 Q-1 4.12 S-2 16.67EL1/PGME/PGMEA 50/20/30 2.9 R-12 P-4 78.20 Q-1 4.65 S-4 17.15EL1/PGME/PGMEA 50/20/30 2.5 R-13 P-5 78.73 Q-1 4.12 S-4 17.15EL1/PGME/POMEA 50/20/30 3.1 R-14 P-1 79.21 Q-1 4.19 S-3 16.60EL1/PGME/PGMEA 50/20/30 2.8 R-15 P-6 80.35 Q-1 4.44 S-2 15.21EL1/PGME/PGMEA 50/20/30 2.9 R-16 P-7 81.24 Q-2 8.55 S-4 10.21EL1/PGME/PGMEA 50/20/30 2.9 R-C2 P-1 81.68 Q-1 4.65 S-1 13.67ELC1/PGME/PGMEA 10/20/70 2.6

TABLE 4 Sensitivity (μC/cm²) LS resolving power (nm) Shape Before Afterlapse Before After lapse Before After lapse Resist lapse of of time (23°lapse of of time (23° lapse of of time (23° composition time C., 1 year)time C., 1 year) time C., 1 year) Example 101 R-1 57.5 57.3 70 70Rectangle Rectangle Example 102 R-2 57.1 56.8 70 70 Rectangle RectangleExample 103 R-3 57.7 57.3 65 70 Rectangle Rectangle Example 104 R-4 58.157.8 70 70 Rectangle Rectangle Example 105 R-5 58.6 58.4 70 70 RectangleRectangle Comparative R-C1 57.5 55.3 70 85 Rectangle Round-top Example101 Example 106 R-6 57.7 57.4 70 70 Rectangle Rectangle Example 107 R-757.5 57.3 80 80 Rectangle Rectangle Example 108 R-8 58.1 57.8 80 80Rectangle Rectangle Example 109 R-9 56.2 56.0 65 65 Rectangle RectangleExample 110 R-10 53.2 53.2 65 70 Rectangle Rectangle Example 111 R-1160.2 60.0 65 65 Rectangle Rectangle Example 112 R-12 55.5 55.2 85 85Rectangle Rectangle Example 113 R-13 56.1 56.0 80 80 Rectangle RectangleExample 114 R-14 53.2 53.0 75 75 Rectangle Rectangle Example 115 R-1553.2 53.0 75 80 Rectangle Rectangle Example 116 R-16 53.2 53.0 70 70Rectangle Rectangle Comparative R-C2 57.5 56.5 70 80 Rectangle Round-topExample 102

Example 201 [Preparation and Coating of Coating Liquid of ResistComposition]

The components shown in Table 4 below were dissolved in a solvent shownin Table 4 below to prepare a solution having a concentration of solidcontents shown in Table 4 below, and this solution was filtered througha polyethylene filter having a pore size of 0.02 μm to obtain a resistcomposition R-21.

These resist compositions were applied onto a 6-inch Si wafer which hadbeen previously treated with hexamethyldisilazane (HMDS) using a spincoater Mark8 manufactured by Tokyo Electron, Limited, and dried on a hotplate at 100° C. for 60 seconds to obtain a resist film having a filmthickness of 150 nm.

Here, 1 inch is 0.0254 m.

In addition, even in a case where the Si wafer is changed to a chromiumsubstrate, the same results can be obtained.

[Extreme Ultraviolet Rays (EUV) Exposure]

A wafer on which the resist film obtained above had been applied wassubjected to patternwise exposure through an exposure mask(line/space=1/1) using an EUV exposure apparatus (Micro Exposure Tool,manufactured by Exitech, numerical aperture (NA): 0.3, Quadrupole, outersigma: 0.68, inner sigma: 0.36). After the exposure, the film was heatedon a hot plate at 100° C. for 90 seconds, dipped using a 2.38%-by-massaqueous tetramethylammonium hydroxide (TMAH) solution for 60 seconds,and then rinsed with water for 30 seconds. Thereafter, the wafer wasrotated at a rotation speed of 4,000 rpm for 30 seconds and then bakedat 95° C. for 60 seconds to obtain a resist pattern having a 1:1line-and-space pattern with a line width of 50 nm.

[Evaluation]

(1) Sensitivity

The cross-sectional shape of the obtained pattern was observed with ascanning electron microscope (S-4300 manufactured by Hitachi, Ltd.). Theexposure dose (EUV irradiation dose) upon resolution of a 1:1line-and-space resist pattern having a line width of 50 nm was taken asa sensitivity (Eop) (sensitivity before a lapse of time).

The resist composition was stored at 23° C. for 1 year to form a resistpattern as described above, and the sensitivity was measured(sensitivity after a lapse of time).

(2) LS Resolving Power

A marginal resolving power (a minimum line width at which lines andspaces (line:space=1:1) are separated and resolved) at an exposure doseshowing the sensitivity was taken as an L/S resolving power (nm)(resolving power before a lapse of time).

The resist composition was stored at 23° C. for 1 year to form a resistpattern as described above, and the L/S resolving power was measured (LSresolving power after a lapse of time).

(3) Shape

The cross-sectional shape of the obtained pattern was observed using ascanning electron microscope (S-4300 manufactured by Hitachi, Ltd.)(shape before a lapse of time).

The resist composition was stored at 23° C. for 1 year to form a resistpattern as described above, and the shape was measured (shape after alapse of time).

Furthermore, in Table 4 below, the content (% by mass) of each componentother than the solvent means a content ratio with respect to the totalsolid content. In addition, the content ratio (% by mass) of the solventused with respect to all the solvents is described in Table 4 below.

The evaluation results are shown in Table 5.

TABLE 6 Resin Acid diffusion control agent Photoacid generatorConcentration Solid Solid Solid Solvent (% by mass) of Resist contentratio content ratio content ratio Concentration total solid compositionType (% by mass) Type (% by mass) Type (% by mass) Type (% by mass)content R-21 P-8 78.60 Q-4 4.88 S-5 16.52 EL1/PGME/PGMEA 50/20/30 1.4

TABLE 7 Sensitivity (mJ/cm²) LS resolving power (nm) Shape Before Afterlapse Before After lapse Before After lapse Resist lapse of of time (23°lapse of of time (23° lapse of of time (23° composition time C., 1 year)time C., 1 year) time C., 1 year) Example 201 R-21 20.2 20.1 27 27Rectangle Rectangle

The resin (P-8) used is shown below. The structure of the repeating unitand a content (molar ratio) thereof, a weight-average molecular weight(Mw), and a dispersity (Mw/Mn) of the resin (P-8) are also shown.

The structure of the acid diffusion control agent (Q-4) is shown below.

The structure of the photoacid generator (S-5) is shown below.

The pKa of an acid produced from the photoacid generator (S-5) is from−10 to 5.

From the results shown in Tables 2 to 5, it was found that the resistcompositions of Examples can exert a good sensitivity, a goodresolution, and a good pattern shape simultaneously in an extremely highdimension even in a case where the composition has been stored for acertain period of time.

According to the present invention, it is possible to provide an actinicray-sensitive or radiation-sensitive resin composition capable ofexerting a good sensitivity, a good resolution, and a good pattern shapesimultaneously in an extremely high dimension even in a case where thecomposition has been stored for a certain period of time; and an actinicray-sensitive or radiation-sensitive film, a pattern forming method, anda photo mask, each using the composition.

Although the present invention has been described in detail and withreference to specific embodiments, it will be apparent to those skilledin the art that various changes and modifications can be made withoutdeparting from the spirit and the scope of the invention.

What is claimed is:
 1. An actinic ray-sensitive or radiation-sensitiveresin composition, comprising a solvent comprising ethyl lactate inwhich one of an L isomer or a D isomer of optical isomers has a ratio of1% or more higher than that of the other.
 2. The actinic ray-sensitiveor radiation-sensitive resin composition according to claim 1, wherein acontent of ethyl lactate is 10% by mass or more with respect to a totalamount of the solvent.
 3. The actinic ray-sensitive orradiation-sensitive resin composition according to claim 1, furthercomprising a resin having a solubility in a developer which is changedby an action of an acid.
 4. The actinic ray-sensitive orradiation-sensitive resin composition according to claim 1, furthercomprising a compound that generates an acid upon irradiation withactinic rays or radiation.
 5. The actinic ray-sensitive orradiation-sensitive resin composition according to claim 1, furthercomprising an acid diffusion control agent.
 6. The actinic ray-sensitiveor radiation-sensitive resin composition according to claim 4, whereinan acid produced from the compound that generates an acid uponirradiation with actinic rays or radiation has a pKa from −10 to
 5. 7.The actinic ray-sensitive or radiation-sensitive resin compositionaccording to claim 3, wherein the resin having a solubility in adeveloper which is changed by the action of an acid is a resin having agroup having a polarity which is increased upon decomposition by anaction of an acid, and the group having a polarity which is increasedupon decomposition by an action of an acid has an acetal structure. 8.The actinic ray-sensitive or radiation-sensitive resin compositionaccording to claim 1, further comprising a compound having a lactonestructure or a sultone structure.
 9. The actinic ray-sensitive orradiation-sensitive resin composition according to claim 1, wherein theactinic ray-sensitive or radiation-sensitive resin composition is usedfor manufacturing a photo mask.
 10. An actinic ray-sensitive orradiation-sensitive film formed using the actinic ray-sensitive orradiation-sensitive resin composition according to claim
 1. 11. Apattern forming method comprising: a resist film forming step of forminga resist film using the actinic ray-sensitive or radiation-sensitiveresin composition according to claim 1; an exposing step of exposing theresist film; and a developing step of developing the exposed resist filmusing a developer.
 12. A photo mask manufactured using the patternforming method according to claim 11.